A/N: Not an update of any of my main stories, I know, but this idea has been bugging me for a while, so I thought that I'd go for it.

Synopsis: We've all read those stories where Harry/Ron/Hermione/Ginny/Luna/random character goes back in time to put things "right", and do so successfully. We've also seen those stories where someone gets the calculations wrong, and they end up at Hogwarts during the time of the Marauders, the time when Tom Riddle was there, or even when the founders' are there.

But what happens when carving just one rune slightly wrong produces far more serious consequences? This story aims to find out, so enjoy!

Why Time Magic Should Be Left Alone!

Chapter 1: Whoops!

"Is it nearly ready?" asked Harry.

Hermione nodded and replied "Almost." as she used her wand to engrave yet another curve into the spherical stone before her.

Harry looked to Luna, who shrugged her shoulders. Harry moved and sat himself down next to her on the rickety old sofa. There was nothing for them to do but let Hermione get on with her work.

The war had gone badly. With over seventy percent of the Ministry of Magic under the Imperius Curse, Voldemort had quite easily taken control over Magical Britain. The Death Eaters had raided Hogwarts, Hogsmeade, Diagon Alley and every other wizarding settlement, forcing people to either swear allegiance to the Dark Lord and take his mark, or die.

Nearly every member of the Order of the Phoenix and the D.A were dead.

Voldemort's influence had quickly spread throughout the other countries of Europe, across into Asia and down through Africa, with Australia and the surrounding Islands falling next. With nearly every single witch and wizard throughout the so-called "Old World" under his control, Voldemort had then turned his attentions to the "New World", the Americas. Despite rumours of so-called "Techno-Mages" who utilized muggle weaponry that was powered by Magic, it did not take long for the two continents to fall. It turned out that the rumours of "Techno Mages" were exactly that: rumours. (Harry wondered why there were rumours of such things in the first place; there was no evidence at all that Magical America was in any way more in tune than their Muggle counterparts than any other magical population on the planet. American Wizards had, in fact, been one of the major driving forces behind the creation of "The International Statute of Secrecy", which came into place not long after the infamous Salem Witch Trials.)

Only a few pockets of wizards who were not loyal to Voldemort remained, and none of them posed much in the way of a threat.

The biggest problem for Voldemort in recent years had, in fact, been Harry's group, who up until recently had been searching for the key to Voldemort's defeat: his Horcruxes. They had found most of them, but each one at a terrible price. Neville's parents and his grandmother had all been killed when the Death Eaters had launched an attack on St. Mungo's Hospital. Each to see them again, Neville had fallen victim to the compulsion charms on the Ring Horcrux that they found in the Gaunt Shack. His death had been slow and painful, with everyone watching, unable to do anything for him, for months until he succumbed. Dean and Seamus had died when the Inferi in the lake that surrounded the location of the Locket Horcrux had attacked them. The worst loss had been of Ginny, Susan, Hannah and the Patil twins when they infiltrated the Death Eater run Hogwarts looking for the Diadem Horcrux. The five went down fighting, taking Draco Malfoy and his cronies, as well as both the Carrows down with them. Harry had taken out Snape and he, Hermione, Luna and Ron had made their escape on brooms, and they had struck no fewer than eight of the Werewolves that patrolled the grounds at night with reductor curses as they fled. Ron's death had been grizzly; Griphook led them to the cup in Gringotts alright, but then he betrayed them, calling for the guards after stealing the Sword of Gryffindor. Ron had given chase, but one of the Goblin Guards drove a spear through him. Harry, Hermione and Luna had made their escape on the back of one of the Security Dragons; a Ukrainian Ironbelly to be precise. Filled with rage at Ron's death, Harry had screamed to the Dragon in parseltongue, urging it to kill all the Goblins it could. The Dragon did so. All the Security Goblins and Wizards that came for them were roasted alive, as were all the Goblins that were seated behind their desks up in the main hall. Death Eaters Travers and Mulciber were burnt up too, and the traitorous Griphook was swallowed whole, Hermione's summoning spell stealing the sword from the back-stabber's grasp.

Harry had hoped that a Goblin Rebellion would keep Voldemort distracted for a time, but it didn't. Voldemort now had more than enough witches and wizards under his control to deal with a Goblin Rebellion, and just thirty-six hours after it began, the rebellion came to an end, with every Goblin lying in an ever expanding pool of its own blood.

With only three of them left, and with no idea how the hell they were meant to get close enough to Voldemort's pet snake Nagini to kill it, all had seemed lost to Harry, Hermione and Luna.

Then, as she was flicking though an old and dusty book on runes one day, Hermione had come across the very thing that they had been wishing for: a second chance.

Although the instructions and the pictographic representations of the final product within the book seemed rather complicated, the idea was actually rather simple: create a magical artefact that would carry them back in time to a point where they could take out Voldemort before he got too powerful. After talking it over, they had all agreed to head back to Harry and Hermione's third year at Hogwarts, as not only was that before Voldemort returned to physical form after being banished from one of his own for thirteen years, but they could also capture Peter Pettigrew and prove Harry's Godfather Sirius Black to be an innocent man.

Using the best Arithmancy-based equations, and employing every single trick in the book on Runes, Hermione had begun to make preparations for their mission and, three weeks after starting, she had been ready to begin carving. Harry and Luna had left her to it; neither of them knew the first thing about rune carving, and instead went around the dilapidated old house they had made their base of operations and doubled, tripled and then quadrupled the already extensive protections that they had on the place.

And now, four days after she began carving the first rune, Hermione was only moments away from finishing.

Suddenly there was a deafening Boom that made all three occupants of the house jump in surprise.

"Oh no!" gasped Hermione.

"What?" asked Luna as Harry ran over to the window to see what was going on.

"The last rune." said Hermione "I messed it up. See? That curving line there is two millimetres too long."

"But you can put it right, can't you?" asked Luna.

"I don't know." replied Hermione "I'll have to do some calculations…"

"I don't think that we have time." came Harry's voice from where he stood over by the window "Voldemort's here."

Hermione and Luna ran over and looked out through the window. About fifty yards from the house stood no less than five thousand witches and wizards. They were still beyond the ward line, but nothing that any of them had put up would stand up to that many wands for too long. Standing before the group, front and centre, was Voldemort himself.

"We need to get out of here, now." said Harry, turning away from the window.

"Okay, just let me finish this last rune." said Hermione, hurriedly. She ran over to the stone she was carving the runes in and began to draw the first of the final three curving lines that the last rune required. There was nothing she could do about the line she had messed up, they'd just have to chance it; after all, what difference did two millimetres make, really?

As she did that, Harry and Luna threw up every defensive spell and enchantment they could think of on the walls, ceiling, floor, window and doors to the room they were currently in. If the main wards fell then these comparatively weak copies would only but them a few seconds, probably ten or twelve, tops. But it just might be enough.

Hermione had finished the first two lines and was just about to start on the final one when a bright orange light flooded the room through the window. The perimeter wards had fallen.

They heard Voldemort's laughter, but it was drowned out by the sound of an explosion. It seemed that the traps had begun to go off. On the exterior of the house, the walls had been engraved with a few runes of their own, designed to begin shooting out powerful bursts of flame should the wards ever collapse. With any luck more than a few of the Death Eaters would meet the same fate as many of the Goblins of Gringotts did during their escape on the Dragon.

Loud crashed and bangs told them that the rest of the house was rapidly being destroyed. Had Harry and Luna not thrown those final few spells up just now, the room would be collapsing in on them.

"Done." gasped Hermione frantically.

Harry and Luna ran over and all three of them each placed a hand on the rock.

"Activate!" shouted Harry and, as the door of the room exploded inwards to reveal Lord Voldemort himself, the trio were whisked away to a different time. Little did they know, their destination was going to be far different from anything they were thinking of.

Harry Potter had absolutely no grace what so ever when it came to travelling by portkey, and travelling through time via rune stone proved to be very similar. Harry fell flat on his face, taking Hermione and Luna with him.

Groaning in pain, they each got to their feet and looked up. They froze.

"I don't think we're in Hogwarts like we were meant to be." observed Luna.

"Forget Hogwarts," said Harry "I don't think we're in England."

He was right. Nowhere in England was there a mountain quite as high as the snow-capped ones in the distance, and the trees and ferns surrounding them certainly did not look like England's native species.

"Okay, so maybe I got the location a bit wrong." said Hermione "The important thing is that we are away from Voldemort.

Noises like those associated with large creatures suddenly filled their ears. Harry turned and marched up the slope next to them, and came to a stop at the top.

"Something tells me that you didn't just get the location wrong." he said.

Hermione and Luna exchanged looks and then hurried to join Harry at the top of the slope. The sight that greeted them caused both of their mouths to drop open.

Before them was a vast plane of low-growing ferns. Walking amongst those ferns were creatures that definitely were not of Harry, Hermione and Luna's world: Magical or Muggle.

Four legged, stocky and coloured in an assortment of greys and dark browns, the creatures were huge: the largest adults had to be thirty feet in length at least, near ten feet in height and looked like they weighed at least eight tonnes each. By far the most distinguishing feature they each bore was their heads. They had what appeared to be large rounded shields extending backwards from their heads, seemingly to protect their necks. Their mouths clearly ended in beaks, not unlike those found on parrots, and they each had three horns; two elongated ones on the top (one above each eye) and a smaller one on the nose.

Hermione gaped in awe "Are those…?"

"Triceratops," answered Harry "Yeah."

Harry had never gotten hit with the "Dinosaur Bug" that seems to strike most boys sometime when they are growing up (living with the Dursleys, he had much bigger things to worry about that a group of large and extinct animals), but he knew enough to recognise one of the most famous dinosaurs of all when he saw one.

"How?" asked Hermione "That small error cannot possibly have been enough to launch us so far into the past, surely."

As improbable as it might seem, however, Harry, Hermione and Luna most certainly had been launched backwards through sixty-five and a half million years into the past before coming to a stop at a point near the end of the Age of the Dinosaurs.

"I wonder what they're making all that noise for." said Harry.

Luna frowned as she observed them "The adults are forming a ring around the youngsters. Oxen do that when there are wolves nearby."

Harry's eyes widened in fear "Hermione, what hunts Triceratops?"

"Tyrannosaurus." she replied.

Not even a second after she said this did it happen. At the opposite end of the fern plane stood a line of tall trees. Out of these came two terrifying monsters.

Standing on two legs that each ended in clawed toes, these creatures were not as long as the Triceratops, but were taller. They were moss-green in colour, and had relatively short forelimbs. Not that they needed them; clearly the killing was done by the jaws. These were opened wide to emit bone-chilling screams as both animals charged out of the trees and ran at an alarming speed towards the Triceratops.

The adult Triceratops stood their ground, instinctively knowing that they were big enough to intimidate these two into a retreat. The youngsters were panicking, but remained trapped within the protective ring of their parents. However it was neither of these that the two Tyrannosaurs were interested in. As well as full grown adults and their much smaller youngsters there were individuals that were of an intermediate size. Not youngsters, they hadn't been rounded up into the middle of the herd, but not being adults, they were not so sure of themselves. Acting on instinct they copied the full-grown animals and formed a wall that would be more than enough to ward off the predators, so long as they held their ground.

Unfortunately for one of them, he panicked, turned and ran. The two Tyrannosaurs gave chase.

"Pack behaviour." observed Luna "See? They're working together to drive it towards those trees."

Harry and Hermione saw that, but both couldn't help but wonder at the sense in driving the animal out of the clearing; surely they'd lose it in amongst the trees.

However the Triceratops never made it to the trees. A third Tyrannosaurus, this one much larger than the other two, exploded out from between the trees and moved to intercept. The Triceratops gave a panicked cry and turned away as if to try and get back to the safety of the herd, but it came face-to-face with one of the smaller Tyrannosaurs. It turned again and found its way blocked by the other. Then its time ran out. The larger Tyrannosaur lunged forward and sank its huge teeth into the animal's back. One bite was all it took to bring the Triceratops crashing to the ground. All three Tyrannosaurs backed off and within less than a minute, a combination of shock and blood-loss ended the life of the herbivore.

Luna, who had studied animals (magical, non-magical and non-existent) for as long as she could remember, marvelled at what had happened. Working as a pair, the sub-adult Tyrannosaurs had caused one of the Triceratops to break ranks and run. They had then driven it towards the full-grown adult and together they had surrounded it. The adult had delivered one powerful bite and then all three had backed off to wait for the animal to succumb to its injury. In doing so, they themselves had avoided any injury they might have received from the Triceratops' long brow-horns.

It was fascinating and truly terrifying at the same time.

"Well crap." stated Harry.

The bigger Tyrannosaurus lowered its head to begin to feed as the two younger animals stood back to await their turn. Clearly there was a pecking order, no matter how hungry the two smaller animals were. Already they were casting glances towards the rest of the Triceratops herd, on the off chance that another vulnerable individual wandered away from the protection of the adults.

"Come on," said Hermione "we cannot linger. We'll be an easy meal for them should they decide to come after us."

Unsure if their magic would work in a prehistoric time period, and not particularly wanting to test it for the first time in clear view of a group of enormous predatory Dinosaurs, Harry and Luna agreed with Hermione and the turned away and hurried back down the slope.

"What now?" asked Harry.

"Well, I'll have to get to work on the rune stone and try and put it right." answered Hermione "Until then, we're stuck here. Had Voldemort not found us, I could've just tweaked a few things and taken us right back to the point we left from."

"Hmm…" mused Harry "Certain death by the hands of Voldemort, or almost certain death by the jaws of a pack of Tyrannosaurus… oh, what to choose, what to choose…"

For that Hermione whacked him around the head.

They wandered into the trees, searching, by unspoken agreement, for a place to hide out as Hermione put the rune stone right.

"Why are there no more animals?" asked Harry after about ten minutes walking.

"I would imagine that the screams of the Tyrannosaurus earlier scared most of them off." said Luna, who had lost much of her dreamy-persona in recent months.

They did soon spot another creature. It was most certainly a mammal, but what kind of mammal, none of them could guess. It was slightly larger than an Opossum and looked a little like a badger… if you tilted your head and squinted a bit.

When they came across it, it was digging for something (probably worms as it looked like a carnivore) but it stopped to stare at them. A little of Luna's old personality came back when she stepped forward and scooped it up into her arms.

"Oh, aren't you sweet?" she cooed as she patted the panicking animal. It calmed pretty quickly, an affect Luna seemed to have on most animals.

"Don't even think about keeping him." said Harry warningly.

"He's right, Luna." said Hermione "He might attract larger predators."

With a sigh, Luna set the animal down and it scuttled off into the ferns.

"What was it, anyway?" asked Harry as they began walking again.

"No idea." said Hermione "Maybe a Didelphodon."

Both Harry and Luna stopped walking and stared at her.

"What?" asked Hermione.

"Nothing." said Harry, shaking his head "I just never figured you for a Dinosaur Enthusiast."

"I'm not." said Hermione "It's just that the summer before fourth year, before I went to The Burrow, my aunt, uncle and cousins turned up. They brought some films with them, including Jurassic Park. It was scary of course, but I still wanted to know it the Dinosaurs in the film were accurate, so I began reading."

Harry shook his head fondly "Of course. Only you could watch a monster film and then want to see if the animals were accurate." after a few moments he added "Were they?"

Hermione shrugged her shoulders "The Tyrannosaurus, Triceratops, Brachiosaurus and Gallimimus were good, but the Velociraptors were not that big in real life, and there is no evidence that Dilophosaurus spat venom, or had that frill around its neck."

Once more Harry shook his head in fondness. Hermione's near-eidetic memory had gotten him out of so many scrapes that he really wasn't all that surprised that she had retained all of this knowledge.

"So come on then," he said "what other creatures are we likely to run into? Any Velociraptors or Galli-whatsits in our future?"

"Well, Tyrannosaurus and Triceratops lived together in North America during the Late Cretaceous." said Hermione "Gallimimus lived in Mongolia, so we won't be seeing them, though it had relatives here at this time. There were two, but I don't remember their names. Both ended in "mimus" though. Velociraptor lived in Mongolia as well, but is extinct by this time anyway. It had a relative here too, but again I don't remember the name."

"Which are predators to look out for?" asked Harry.

"Tyrannosaurus, obviously, and the raptor." answered Hermione "I can't remember if the 'mimus was a carnivore or not. It has a similar body shape to the raptors."

Not at all pleased with the number of creatures lurking in the forest that would like to make a meal out of them, the trio continued on in silence.

Slowly the ground began to rise, and the trees thinned out. They had reached the foot of one of the smaller mountains in the area.

Harry led the way up, with the other two following behind. Soon they were higher than the trees.

The ground seemed to be quite loose in places, stones came free rather easily and, in between those stones the earth was very dark; almost black.

"It's Ash." observed Hermione from the back of the group.

"A fire, do you think?" asked Harry.

"Maybe," said Luna "Either that or the mountain is an active Volcano."

At those words they all froze and looked to the top of the mountain. There didn't seem to be any smoke billowing out of the top, nor any molten lava, for that matter.

"Well if it is active," said Harry "Then with any luck the Dinosaurs might knew to stay away from it, and hopefully we'll get out of here before the thing does erupt."

They climbed a bit higher, but it wasn't long before Luna stopped.

"What's the matter?" asked Hermione, coming to a stop behind her. Harry turned around to look at them.

"I sensed something…" Luna replied "There's an animal nearby."

Harry and Hermione looked around, but neither of them saw anything.

"I can't see anything, Luna." said Harry, but mere seconds later a shadow passed over them.

All three of them looked up and saw a massive flying creature soar through the sky overhead. It emitted a cry and suddenly swooped towards them.

"Down!" yelled Harry, throwing himself down towards the ground. Hermione and Luna mirrored his actions, throwing their hands over the backs of their heads. Their hair and clothes blew in the breeze generated by the creature flying so close to them.

Harry looked up and saw the creature flying off.

"Stay low and move." he shouted and they began to crawl frantically up the mountain.

Another cry told Harry the creature was close again. With another shout from him, they all threw themselves flat on the ground again. There was a scream and Harry looked up. To his horror he saw the creature flying off with Luna clutched in its talons.

Harry stood and ran a hand through his hair as Hermione pushed herself to her feet. They watched as the huge creature swooped around and landed higher up on the mountain. It stopped only briefly before taking flight again, this time gliding down towards the forest.

"She's still up there." said Harry "It didn't wait long enough to eat her. Come on."

With a look over her shoulder at the flying animal, which now seemed to be heading towards the fern plane where the Tyrannosaurs had attacked the Triceratops, Hermione nodded and she and Harry began a rapid climb up the mountainside.

"I knew Dinosaurs grew big, but that Pterodactyl was huge." said Harry as he and Hermione scrambled uphill.

"That wasn't a Pterodactyl," said Hermione "It's called Quetzalcoatlus, named after the winged-serpent god Quetzalcoatl."

"A Kwetso-what-us?" asked Harry.

"Quetzalcoatlus." said Hermione "Probably the biggest flying animal ever, and technically not a Dinosaur."

Harry frowned "Does it look like a Dinosaur?"

"Well, a bit." said Hermione.

"Does it sound like a Dinosaur?"

"I suppose."

"Then it's a Dinosaur." said Harry, simply.

Hermione shook her head, but said no more. Now wasn't the time to explain that not all giant prehistoric reptiles were Dinosaurs and that species classification was a lot more complicated than that.

They got the place where the Kwetso-doofer (as Harry would from now on refer to it) had landed and found Luna. She was unconscious, and had a few scratches on her, but otherwise seemed fine. Hermione shook her gently and she woke up.

Harry meanwhile, was staring at the large cream-coloured, egg-shaped stones that surrounded Luna.

"What do you suppose these are?" he asked.

Hermione looked at them, rolled her eyes and decided to take a leaf out of Harry's book.

"Are they the shape of eggs?" she asked.

"Yeah."

"Are they the colour of eggs?"

"I suppose."

"Then they're eggs."

Harry suddenly went very still "Eggs of what?"

That question was answered when one of the eggs cracked. The trio backed off as pieces of eggshell broke away. A large hole formed, and the head of a baby Kwetso-doofer emerged, its little yellow eyes locked onto them.

"Run." said Harry and the three of them turned and pegged it up the slope as fast as they could. Loud and rapid chirping told them that the other eggs were hatching fast.

A little further up, and a lot of the way around the mountain, they found a small cave. It went into the mountainside no more than fifteen feet, and was less than six feet wide at its widest point, but it was certainly more than they could have hoped for.

"Well, this seems reasonably safe." said Harry, looking around "I don't think the Tyrannosaurus will bother climbing this high, so all we've got to watch out for is that Kwetso-doofer."

"Quetzalcoatlus." corrected Hermione.

"That's what I said." replied Harry "Now, let's see if we can get some wards up."

Thankfully their wands did work, and with a bit of spell work, Luna made their cave unnoticeable to animals (a handy trick when observing rare animals like she used to do with her father), Harry got a little fire going and Hermione conjured up some furniture.

Then Hermione set herself down and began examining the rune stone, hoping to spot a way to get home (or somewhere a little nearer to home than Montana during the Late Cretaceous).

Harry and Luna stood at the entrance, surveying the scene before them. From their height it was difficult to make out too much, but they could see a huge body of water to the east. The forest that they had come through was actually only one of several. None of them were that large, and they were scattered about between large areas of low growing ferns. There seemed to be huge areas, however, where nothing seemed to grow at all.

Harry conjured up a pair of binoculars and scanned the scene before him. The Kwetso-doofer was still soaring over the forest. The big Tyrannosaurus was asleep in the shade and the two younger ones were squabbling over the remains of the kill. The Triceratops herd had left.

Down on the sandy beach that lined the large body of water, a lone Dinosaur was ambling along.

"Hermione what's this Dinosaur?" he asked.

"I'm busy." said Hermione, staring at the rune stone, trying to figure out what went wrong and how to put it right.

Unperturbed, Harry began to describe the animal "It's large and black, but with yellow markings. It walks on four legs and looks like it has armour, you know, like an Armadillo's only… not. Oh, and it got a massive thing on then end of its tail, sort-of like a club."

"Ankylosaurus." said Hermione "Now please be quiet. I'd like to get out of here before becoming a Dino snack."

Harry and Luna looked at each other, shrugged, and then made their way into the cave. That sat down on some armchairs that Hermione had conjured and waited in silence until Harry broke it."

"Hermione, a book on Dinosaurs might be a useful thing to have. Is there any way you can conjure one?"

In fact there was. So long as you remembered the book in question, someone with a well-organised mind could conjure up a book from thin air, word for word. Fortunately for them, Hermione's near-eidetic memory, coupled with her excellent Occlumency shields, made her the perfect candidate for such a task. With a simple flick of her wand, five large books appeared in thin air and landed with thuds onto the floor at Harry and Luna's feet.

"Now be quiet." said Hermione.

Harry and Luna exchanged looks again, shrugged, each picked up a book and began to read. Harry landed on a useful page very quickly. It had a large picture on it, depicting a scene from a period in the age of the Dinosaurs. The text on the opposite page identified each of the creatures. The only names Harry recognised were Stegosaurus and Brontosaurus, though Brontosaurus was only mentioned as being the former name of the Apatosaurus. With neither Tyrannosaurus nor Triceratops listed as being on the page, Harry flipped through the book until he found a picture that did show the two animals, along with about ten others.

Both Harry and Luna settled themselves down for an evening of reading. Anything to help them to survive in this prehistoric world they knew very little about.

A/N: So what do you think? Love it? Hate it?

In case anyone is actually interested, this story is taking place during the Maastrichtian Stage of the Cretaceous period, the last part of the Age of the Dinosaurs. They are in a location what will one day be the U.S. state of Montana, and the animals that they encounter are from the Hell Creek Formation.

Species encountered so far are:

Tyrannosaurus rex.

Triceratops horridus.

Quetzalcoatlus (species unidentified).

Didelphodon vorax.

Ankylosaurus magniventris.