As the Doctor and Hermione continued down the main road, people started to stare at them. This wasn't unusual for the Doctor, who tended to tune that sort of thing out, and Hermione was used to being different, so neither one noticed. Hermione was busy taking it all in; the sights, the sounds, and especially the smells. There was no substitute for this type of learning; not even Wizard photos could convey this sort of experience. The absence of Romans became even more glaring. On the side of the road, they saw a temple, where a man was standing near the outdoor altar.

This man was not a typical man; he was a Celt, but he was standing in front of a Roman temple. The temple was tall, with an altar in front of it. He was about forty years old, with only a few teeth left. He appeared to be shouting. Noticing this, they Doctor led Hermione a little closer to him.

"They are here!" he shouted. "They have come! They have found us! It has come to pass!"

The Doctor walked over to the man. "Who's come? What are they going to do?" he asked in a friendly manner.

"They are here! They want to – want to…" he trailed off, mesmerized by the vast, blue sky.

The Doctor wasn't very satisfied with this answer, so he probed a bit more. "Are they trying to hurt you? Are they malevolent?"

"Yes! First they took them… soon they shall take us!"

Hermione wasn't very pleased with this vague use of pronouns, but she was certainly interested. She was always up for a good mystery, and this seemed like one. Although she was skeptical of the man, who could very well just be mad, she secretly hoped that there was something more sinister going on.

"So, how do you know about them, my good sir?" the Doctor asked.

"The birds have fallen… they say that during the last days, the birds shall fall…"

A switch went off in Hermione's head. Her studies of Latin, which had done their job of immensely improving her incantations, had taught her a thing or two about Roman culture as well. The people of the Roman world were fascinated, just as many humans still were, with knowing what would happen before it actually did. One of these "methods" was through examining the patterns of birds in the sky. It seemed absurd, but the people took quite a bit of stock in the idea that flocks of birds' patterns were real ways of predicting the future. She tried to remember the name of this type of person. Ah… au… augur! She thought to herself. This man was an augur, a predictor of the future and observer of birds. She normally would have chuckled at the ludicrousness of it all, but she remembered the tale of Julius Caesar's death and its prediction, so she decided not to mock this.

"Doctor," she said, wanting to share this recent discovery.

"Yes, Hermione?"

"See, he's one of those… augures. They –"

"—watch the birds in the sky," he said finishing her sentence. She was surprised at how often their minds ran on the same parallel already. "I've visited ancient Rome more than a couple of times, I've seen 'em too. Good deal of rubbish, if you ask me, but harmless nonetheless. Always have been a big fan of birds," said the Doctor with a grin. The man returned to yelling and the Doctor knelt over the altar, where the remains of a small blackbird lay. He put on his brainy specs and examined it with a stick that he had found.

"The strange thing is, Hermione, a question arises: why are the birds dying? Birds don't just fall out of nowhere, you know. Has to be some cause, some reason… aha!" He removed his sonic screwdriver from his pocket and pointed it at the bird. It began to shine with a faint green. Hermione's brow furrowed. What was this thing?

The Doctor noticed her confusion. "Oh, it's a sonic screwdriver. Shoots out sonic waves and, you know, does stuff." He had a knack for explaining things to children, but Hermione, perfectly capable of understanding, was a little frustrated at the simple answer. Nevertheless, she bent over and examined the bird more closely with him.

"So, Doctor, this isn't a normal occurrence for Roman Britain, right? There's got to be something at work here. What would make hordes of birds die and still have a green residue back in 81 A.D.?"

"Well, lots of things," he said, before rattling off a bunch of possible causes. "There's a chance of disease, of course, but no, it's got to be different than that… could be some type of predator, or malnutrition, or –"

"Doctor! What about something more modern? Don't certain chemicals leave this type of trace?"

"Or…. Or or or… radioactivity! Brilliant, Hermione Granger, simply brilliant! There's got to be something around here, something giving off radiation. See, in cases like these, you've got to think like the natives. When in Rome, do as the Romans do!" he said with a silly grin.

Hermione concentrated. She was happy she hadn't given up all Muggle scientific learning once she had gone to Hogwarts, especially in the fields of science. What could be giving off this type of radiation in ancient Britain? What did Britain have that was abundant, radioactive, ancient and…

"I've got it!" she shouted. "Coal! Britain's got loads of coal!"

"…and coal has carbon-14! Radioactive isotope, got plenty of particles to shoot off. Granted, it wouldn't be in amounts like these, but still. I like the way you think, Hermione."

She smiled. "Thanks, Doctor. Same to you."

"So, if we can somehow find the source of all this coal, we could figure out what's killing the birds," he said, pacing on the steps of the temple now.

"Do you have some sort of detector?" Hermione asked, knowing that the TARDIS had plenty of alien technology that was certainly advanced enough to find a little of radioactivity.

"Well, not exactly. But no need to fear, Miss Granger, we'll build one!"

"Er… build one?" she asked. She was always more of a learning type of person, not an engineer. Spells were good enough for her.

"Yes, yes, of course! I'll need a pot, some string, the sonic, a piece of cloth, and…" he said, listing various items aloud. "Hermione, why don't you look for the cloth and string? I'll gather up the rest, and we'll meet back here in ten minutes."

-x-

They reconvened at the altar in ten minutes' time. The Doctor had a bunch of supplies in his hands, and Hermione had retrieved the cloth and string, after slyly plucking them from an unsuspecting merchant's cart.

"Well, Hermione, I've got nearly everything, but there's just one more thing I couldn't find. The most important bit, too, I'm afraid. We need a sample of the coal itself."

Hermione was a little disappointed, but remembered that she still had her wand in her pocket. She grinned, pulled it out, and shouted. "Accio coal!" she pronounced. Sure enough, coal came flying towards her from the south. The Doctor looked quite shocked.

"You… what? What? What on Gallifrey was that?" The Doctor was taken aback by her Summoning Charm. There was obviously a lot that he had to learn from her, event though she was young.

"Oh, just some magic. We do learn things at Hogwarts, you know, Doctor," she said playfully. He grinned and thanked her. "Hermione Granger, magic extraordinaire. Brilliant!" He set to work fiddling with the set while Hermione examined the dead bird. It looked so small… so innocent. Although her cat, Crookshanks, wasn't very fond of birds, she certainly had a soft spot for them.

The Doctor had finished after a few minutes. "Well, here we have it! It's no Geiger counter, it's a bit shaky, yeah, but it'll do. Roman Radiation Detector!" He cocked his head to the side and winked.

"Great! Now we need to find the source, right, Doctor? When I summoned the coal, it came from the south. Should we head that way?"

"Seems like a good enough plan to me," he said. Her powers of deduction wouldn't let him stop smiling. The way she analyzed, observed, and made split-second decisions from them was brilliant. It reminded him of himself as a boy (and now, of course).

They set off to the south, running until they reached the Thames. There, they found a rickety bridge that crossed Londinium's river. Cautiously, the Doctor crossed, but Hermione didn't appear to be afraid at all. When he asked her why, she replied simply: "I'm a Gryffindor, Doctor. We're brave."

They continued down to the south until they reached the outskirts of town. There was a ramshackle old hut a few meters from the path. They decided to examine it further.

"So, Doctor, what would make the radioactive carbon deep below the ground kill the birds in the air?" Hermione asked, curious at how this poisoning worked.

"You know, dear, I'm not really sure," he said, absentmindedly observing the hut. "It does seem a bit peculiar though, doesn't it?"

"Very. Radioactivity isn't really found in such large doses in nature, so it just doesn't add up…"

"Exactly, which is why this makes it all the more interesting. Something's up here, something very, very suspicious…"

Hermione looked inside the hut and saw a hole in the ground, where a ladder stood, leading into the darkness of the deep. "So if coal is generally found underground, we should probably look in mines. This looks like a mine over here, Doctor," she said, moving inside for a closer look.

"Brilliant! And look at that pile of coal over on the floor there. That must have been where the coal you, er, called, came from. Let me try the detector…" He pulled some strings on the device and sure enough, a spark appeared, showing that there was radioactivity in the area.

"So, let's go! This is the only logical place the coal could have come from, so it makes sense enough to be here."

"Yes ma'am! I'll go first, just in case. Allons-y!"

Hermione followed the Doctor, who was beaming from ear to ear, down the ladder into the dark mine. The Doctor was happy; he had finally found a companion who was just as brilliant, logical, and daring as he was. This is definitely better than being alone, he thought. Definitely.