Chapter 1:

"Happy birthday boss!" Scratch said as he and Grounder walked/rolled into the lab in Robotnik's fortress while carrying a cake. "We made your favorite evil cake just like you asked". Robotnick was sitting in a chair at a computer mainframe and when he didn't answer them after a few seconds Scratch added, "Something wrong your vileness?" Robotnick replied in a distraught voice, "Another year gone and I still haven't dealt with that hedgehog. I've tired scheme after scheme after scheme, and nothing worked." The computer screen started showing images of various plots he'd tried, including a schematic for the stopper zapper. Robotnick continued, "Soon I'll be and old man and there won't be anyone to continue my evil ways in my place." As he said the last bit the computer showed an image of the decrepitzer. Robotnick looked at it for a second and suddenly exclaimed, "That's it!" After a moments pause he addressed Scratch and Grounder: "Ready your best hedgehog nabbing traps, but do not leave the fortress until I command you to. This time Sonic will be mine!" He trailed off into an evil laugh.

Later, Sonic and Tails were running around a hilly area of Mobius and had just stopped in a deserted valley to give Tails a break. While Tails was catching his breath, Sonic asked "I wonder what's up with Robuttnick? He hasn't tried anything in a whole week." Tails replied, "I don't know Sonic, maybe he's retired." Sonic responded, "Nah, I don't think he'd give up that easily." Sonic started to sniff the air, "You smell that Tails?" he asked. Tails sniffed and replied, "Smells like a chilidog, but why would a chillidog be way out here?." Sonic answered, "Its probably another lame trap by those badnicks but that's cool, it saves me the trouble of making lunch."

Sonic quickly found the source of the smell: a chilidog on a plate on top of a wooden table with a checkerboard table cloth with 2 chairs next to it. After spotting it, he told Tails, "Wait here until I give the signal" after a few seconds pause he added, "I care about you little bro so I'd hate to have anything happen to you" He zoomed in and ran over the hidden pitfall Scratch had set up before the cover over the pit could collapse and with a combination of speed and deception tricked grounder into trying himself and Scratch up in his (Grounder's) restraining machine. Then he whistled for Tails who came flying over, mouth watering.

Sonic and Tails were about to sit down to enjoy lunch after laughing at Scratch and Grounder trying to free themselves from the metal tentacles of the machine they were trapped in when Tails heard a strange noise nearby. He turned his head and saw Robotnick aiming some sort of weird raygun at Sonic from the cockpit of his eggomatic hovercraft and pulling the trigger. "Sonic, Look out!" Tails exclaimed and tackled him out of the way of the pink ray, however this caused Tails to get hit by it instead. Sonic saw Tails collapse while glowing pink and turned to face Robotnick. "You'll pay for that!" he said and charged up a Sonic Spin. Scratch and Grounder came running over to assist their master but Sonic's spin cut them to metallic ribbons. Robotnick tried to shoot Sonic again but when he pulled the trigger nothing happened. He looked at the raygun's display and to his horror it said, "Energy depleted." Robotnick looked up in time to see Sonic flying up at his Eggomatic and had just enough time to say "Oh no" before he and his vehicle were sent flying into the distance. The impact caused Robotnick to drop the raygun which fell and smashed to pieces on the ground.

Sonic ran back over to the table to see what had happened to Tails, his troubled mind filling with horrible thoughts about what Robotnick's weapon could have done to his little brother. He saw Tails's shoes, socks, and gloves on the ground and between them was a small brown fur ball. As Sonic got closer he noticed the "fur ball" was actually a baby fox. Sonic saw that the baby fox was sucking its thumb, he then noticed that it had two tails. A glint of light caught his eye and Sonic looked over at the pieces of robotnick's raygun. One caught his eye, it seemed to be a label and it read "regression ray". Sonic read the label, and then looked back at the baby fox. Now it all made sense.

Chapter 2:

Sonic pondered what he should do next for a sonic second before thinking aloud: "Professor Vonschlemmer should know how to reverse this raygun". Then he started picking up and "pocketing" the pieces of the regression ray along with Tails' shoes and gloves. (Author's note: since its shown in cannon Sonic is able to store 2 sets of camping gear and much more on his person somehow, I figure he can "pocket" the regression ray parts) Sonic walked over to Tails and was about to pick him up and speed off to Professor Vonschlemmer's lab when he saw a yellow puddle forming around Tails's crotch. As Tails wet himself, he started crying. Sonic was nervous for a second before reminding himself "That's Tails: what kind of big brother backs down from caring for his little brother?". As Sonic got some stuff out of his unexplained inventory space he said "Its ok Tails. I'm here for you little bro". After cleaning up Tails with some napkins and water from a nearby stream, Sonic picked him up and sped off towards the nearest department store.

Once Sonic arrived at the store he wanted, he looked down and noticed that Tails had fallen asleep in his arms. Sonic wasted no time in buying everything he needed. After he paid for his purchases, he carried Tails into the bathroom and set him on the changing table, noticing that Tails was starting to wake up as he did so. Sonic quickly strapped Tails to the changing table and got out a disposable diaper. As he applied a dusting of baby powder and taped the diaper onto his little bro, he couldn't help but notice the cute expression he was getting from the baby fox. Sonic inspected his handiwork and reflected that he knew what he was doing somewhat since Tails wasn't fully potty trained when they'd first met. After Sonic had unstrapped Tails from the changing table Tails held up his arms as if he wanted Sonic to carry him. "Awww" Sonic said and picked up Tails with a smile. Then Sonic's stomach rumbled. "Oops, forgot about Lunch" he said rhetorically and ran off to find a restaurant.

Sonic found a small Diner and managed to get a table that was relatively private: He'd saved the restaurant owner from a robot attack once so the owner was glad to help him out in return. As a well known hero of mobius Sonic had feared he'd be asked awkward questions about Tails like "Who's the mother?" if he wasn't careful. The Diner didn't have any baby seats so Sonic sat Tails down next to him directly in the booth. A few chilidogs later Sonic looked over and noticed Tails staring longingly at the plate of food and trying to reach for it. "How could I forget?" Sonic asked out loud, "Your hungry too". Given the current situation Sonic didn't want Tails to choke so instead of giving him chili dogs he got out a bottle of milk. Then he placed the baby fox in his lap and put the bottle in his mouth. Tails started drinking the milk and looked very relaxed as he did so. After he'd finished the bottle Tails once again started reaching for Sonic's food. Sonic figured out the message and asked the waiter for some warm milk. While he was waiting for the milk to arrive, Sonic looked down at Tails and noticed that he seemed content to snuggle in the blue hero's lap. Then he noticed a small wet spot forming on Tails' diaper and worried that he might start crying again but when Tails stuck his thumb in his mouth and looked up at him cutely instead Sonic's thoughts changed to "He's so adorable like this". The waiter brought the milk which Sonic transferred from the glass it came in into the bottle he'd purchased earlier and fed Tails again. Afterwards Sonic held Tails up with one arm and patted the baby fox's back with the other until Tails let out a small burp. After paying the bill, Sonic thanked the owner and set off for Professor Vonschlemmer's lab.

One speedy run later Sonic was standing outside of Professor Vonschlemmer's lab with Tails in his arms. Sonic rang the doorbell and waited. From inside he faintly heard a voice say "Why is the Milkman here at this hour?" followed by footsteps. The door opened to reveal Professor Vonschlemmer. "Hi Professor Vonschlemmer", Sonic started to say. "Professor? Where? Oh wait, right here" was the scientist's response. He looked at Sonic and said, "Sonic, come in come in." Sonic stepped in while still carrying Tails. After shutting the door Professor Vonschlemmer asked "What can I do for you?" Sonic held Tails in one arm and set the pieces of the destroyed regression ray on a table with the other. Sonic pointed to the regression ray parts and said, "I need you to find a way to rebuild this regression ray and reverse its effects." Professor Vonschlemmer looked like he was pondering for a second, and then asked. "Where's Tails?" Sonic fought the urge to face-palm. For a brilliant scientific mind, Professor Vonschlemmer sure was slow on the uptake sometimes. "He's right here professor," Sonic said with a hint of annoyance while holding Tails out, "Robotnick zapped him with a raygun whose pieces I just mentioned and he wound up like this." Professor Vonschlemmer considered a second and then said, "Ok Sonic, I'll start on it right away." Sonic figured that he'd get his solution sooner if he didn't distract the professor so he went back outside.

Sonic found a deserted field a short distance from the lab and sat down on a tree stump while still carrying Tails. Then he heard soft farting noises coming from his little bro. Sonic steadied Tails on his lap with one hand and pulled the back of his diaper back slightly with the other. The smell that reached his nose told him all he needed to know. Sonic got out a changing pad and supplies, and set Tails on top of the pad on top of the stump. He removed Tails's used diaper, cleaned him up, and after applying more baby powder taped a new diaper on him. Afterwards he let Tails crawl around for a bit while under close supervision.

Tails' playtime was cut short when Sonic heard a shout of "Someone help me!" He thought he recognized the voice but couldn't place it. Sonic ran off with Tails in tow and came upon a female hedgehog tied up on top of railroad tracks. He realized that he'd need his hands to save her so he set Tails on the ground and said, "Wait here. I'll be right back". Sonic quickly grabbed the female hedgehog, who was heavier then she looked and untied her. "Anything for a babe in need" Sonic said flirtatiously. However the hedgehog replied in a not quite mono tone, "You fell for it, hedgehog." Then a compartment in her chest opened and sprayed gas from a can labeled, "Deep Sleep Gas" at Sonic. Sonic reacted fast enough to not fully lose consciousness on the spot but as he fought to stay awake, he saw the Eggomatic descending on the spot where he'd left Tails. Sonic didn't want to be captured as well so he ran away and finally collapsed in a forest a few miles away.

Chapter 3:

Sonic woke slowly until he realized he'd face-planted in the middle of a forest. Then the events right before he collapsed all came back to him. "I thought I'd recognized that voice" he said, "Its the same one as the last female impersonator bot that tried to charm me which means... Tails!" Sonic realized that he'd left Tails alone and rushed back to the place where he'd left his little bro. However instead of a baby fox he found a note that said,
"Sonic, if you ever want to see your foxy friend again, come to my fortress and surrender yourself - Yours Evilly, Dr. Robotnick"

Sonic ran off towards Robotnick's fortress. He wasn't planning on surrendering, but he had to at least play along until he came up with a plan. He arrived and was about to smash open the door when he heard a voice say "I wouldn't break that door in, hedgehog." He looked up and saw Robotnick standing on a balcony. "What have you done with Tails?" Sonic questioned angrily. Robotnick replied, "He's fine, but he'll only stay that way if you surrender. See for yourself. Robotnick held up a TV monitor and as the image came on Sonic expected to see Tails in chains in the dungeon with something threatening poised at him. What he did see however made him raise an eyebrow. Robotnick noticed Sonic's reaction and said, "What. Do you think I'd lock up a harmless little baby? Why would I do that when he'd make a great evil sidekick some day, and when I'm done with you, you'll be in the next crib over so I can raise you as my evil successor!" Sonic replied, "I knew you were thick headed Robuttnick, but do you really think you can get me to stand down with a video of an empty crib?" Robotnick looked confused before turning and seeing that monitor did indeed display an empty crib. "Ahh!" he said, and after recovering himself he added "Scratch, Grounder! Stall that hedgehog. I have a brat to catch." Sonic started sawing his way in while Robotnick ran for the nursery he'd recently added to his fortress.

Sonic had sawed through a few metal doors when he came to a more open room. In it were Scratch and Grounder, inside two large battle mechs. "Going somewhere?" Scratch asked Sonic. Grounder added, "You'll have to get past us to get there." Sonic ran at the two mechs but stopped when laser fire from previously concealed wall turrets crossed in front of him and almost hit him. "Looks like our master turned on the automated defense lasers". Scratch gloated. "He really does care about us" Grounder mused aloud. Then a laser burned a hole through the chest of Grounder's battle mech while others started shooting random patterns on the walls. Sonic dodged around one end of the room and let the lasers turn the mechs at the other end into metallic swiss cheese. The door at the other end of the room opened suddenly so Sonic ran through to the next room. Scratch and Grounder tried to follow but where crushed by the door as it closed again. "Even robotnick isn't that bad of a shot, I wonder who's controlling those defenses then?" Sonic wondered aloud.

Tails watched the monitors of Robotnick's main computer with an amused expression. After falling asleep while waiting for Sonic to return He'd woken up in a crib in a strange place, and he was alone. He'd used his tails to fly out of the crib and crawled over to a room with a big computer in it. Though he couldn't fly for very long, he could get out of his crib and onto the keyboard for the big computer. Once he was there he'd started pressing buttons randomly, enjoying the noises they made. Tails suddenly heard a shout of "Get away from my computer you brat!" and turned to see Robotnick standing in the door to the computer room looking mad. However as he turned his hand touched a button and Robotnick looked down to see that the floor below him was gone: Tails had pressed the trapdoor button, but since Robotnick was too round to fit though the trap door he got stuck instead. Robotnick continued to say angry remarks until Tails accidentally sealed that entrance off. His next button press evoked a recorded voice that said, "Missile offense system activated"

Sonic was working his way through the fortress dodging the seemingly randomly targeted defenses when he looked out the window and saw the giant gold statue of Robotnik that adorns the front of his fortress get struck by a barrage of missiles and fall flat on its face. "Ol' Buttnick will have a hard time fixing that" Sonic laughed to himself and once the doors opened again he sped off towards the control room. He was almost there when he heard a recording say. "System overload: self destruct sequence activated." Sonic ran through one more door and saw Tails on top of the keyboard for Robotnick's mainframe, pressing buttons randomly and giggling away. The door at the opposite end of the room opened for a second and he saw Robotnick trapped in a trap door. "Wow" Sonic said as he realized what had happened, "You did all that? Your amazing keed!" However one of the monitors showing a countdown reminded him that he had to escape. Sonic grabbed Tails and vaulted out a window a few rooms down. Robotnick noticed him leave and said, "I HATE that hedgehog, and that baby fox too!"

Sonic ran back to Professor Vonschlemmer's lab with Tails in tow. He knocked on the door and Professor Vonschlemmer opened it. "Come in" he said, "I've reversed Robotnick's raygun's fuction, now all we need to do is use it on Tails." Tails was asleep again, so Sonic set him on a chair and fired the now reversed Raygun at him. Tails began to glow pink and grow to normal size. Sonic removed a now too small diaper and cleaned Tails up one last time before putting his brother's shoes, socks, and gloves back on. Just after Sonic had thrown out the used diaper, Tails began to stir. He opened his eyes and Sonic asked, "How you feeling Keed?" Tails replied, "I had the weirdest dream, Sonic." Sonic asked, "What was it?" Tails answered, "I dreamed that I was a baby again and you were taking care of me. It was a really nice dream." Sonic inwardly felt very happy that he'd done a good job but replied, "I'm glad you enjoyed it little bro" and pulled Tails into a hug.