One day in Unikingdom, Dr. Fox was working on an important experiment. She was currently working at her desk with a test tube in her paw that was filled with a strange purple liquid, "Alright, now if my calculations are correct..." she mumbled before putting a single drop of another liquid into the test tube, making its contents change color to a yellowish tinge, "OK, that went well. Now for the test." she said as she turned her attention to a dead plant on her desk. She poured a little bit of the liquid into the plant's pot, causing it revert from its withered state to fully green and flourishing, "Success! My de-aging serum is complete. Now that that's done, I can get started on making that perfect lemonade recipe that Unikitty asked me to make." Dr. Fox said while writing a clipboard.
Meanwhile, Unikitty was just heading into the castle, tired and ragged, "Ugh, what a day..." she said.
Richard was cleaning the floors as she walked in, he stopped when he saw her enter, "Hard day, princess?" he asked.
"Tell me about it, first I had to help Hawkodile rearrange is workout gear, then I had to help Dino Dude get new wheels fitted on him, and then I needed to help the theatre group rehearse their new five-hour play, "Traffic Jam: The Musical. Never before have I had to hear the phrase 'bumper to bumper' so many times." Unikitty explained as she flopped onto the couch.
"Well princess, no one said ruling a kingdom was going to be easy." Richard said.
"I try to make it fun Richard, but even that is a ton of hard work. Oh, how I miss those carefree days." Unikitty said.
"Well, you just try to relax while I go see about buying theatre tickets." Richard said while floating off.
"Might as well go see what Dr. Fox is up to." Unikitty said with a sigh before heading down to the lab. She found that Dr. Fox was not there, "Doc? Are you in?" she called out. She eventually came to the desk to find a whole beaker filled with the serum the scientist was working on earlier. Her eyes lit up in excitement as the yellowish color was what caught her attention, "This must be the perfect lemonade that I asked Dr. Fox to make! Better test it ahead of time." she said before she took small sip, "Mmm, that's pretty good." she said before she chugged down the whole beaker.
During all this, Dr. Fox was in her study, trying to figure out a complex calculation on the lemonade's texture. Her thoughts were interrupted by the sound of breaking glass, "Who's there?" she asked as she ran out to inspect what was wrong. What she found definitely shocked her, "Oh my gosh..."
Later on, Puppycorn, Hawkodile, and Richard entered the lab due to being called in by Dr. Fox, "You needed us to see something Doc?" Puppycorn asked.
"Well, how else should I put this?" Dr. Fox nervously said before scooting over to side to reveal a surprising sight. It was Unikitty, except now she was much smaller, her horn and ears were shorter as well. A blue bow was tied around her horn and a light pink bib was tied around her neck. She was also wearing a white diaper with pink frills on the waist and leg holes. She babbled happily as she saw them while waving her paws around adorably.
"Doc, please tell me that's not a baby Unikitty?" Richard asked.
"That's definitely a baby Unikitty." Hawkodile whispered to him.
"I just said to not tell me that." Richard scolded.
"She must've drank the de-aging serum that I had on the desk." Dr. Fox explained.
"Doc, how many times do I have to tell you? Please label your serums." Richard said.
"Guys, I know we're all a little miffed here." Dr. Fox said.
"Well, I couldn't be happier, I'm a big bro now!" Puppycorn cheered.
"But, I can fix this. I just need to reverse engineer the serum and we'll be all good." Dr. Fox said. She noticed a tugging sensation on her tail, causing her to turn around and see Unikitty chewing on it. She pulled her away and addressed her, "No Unikitty, no biting my tail." Unikitty then started to pout while her cheeks turned red, "Uh..."
"This is what I was most worried about, whenever she didn't have her way as a baby, she always threw these really big tantrums." Richard said with worry.
Unikitty was getting angrier by the minute, her fur starting to turn red, "Uh, Unikitty, its OK. You can chew on my tail if you want to. Please don't burn the lab down." Dr. Fox said in a desperate attempt to calm down her de-aged friend. It was in vain, as Unikitty continued to get angry, reaching her tantrum.
"Wait, I got an idea!" Richard said before floating upwards and then returning with a butterfly-themed pacifier, "Stand back!" he shouted as he flung the pacifier in Unikitty's direction. She was about to start screaming when the pacifier entered her open mouth, stopping the disaster that was to come. Unikitty started to suckle the pacifier, her fur turning back to pink as she started to calm down, smiling brightly as she suckled, "Phew, crisis averted." Richard said in relief while picking up Unikitty.
"So, the plan is we take care of Unikitty while you fix up that serum, right Doc?" Hawkodile asked.
"Exactly. Don't worry, I'll try to have it done as soon as I can." Dr. Fox said.
Unikitty turned out to be quite the troublesome baby, always floating around and almost breaking things. She even couldn't stop getting herself into danger, whether it was almost falling off the balcony or almost making an unsteady stack of items collapse right on top of her. The gang was there to save her, but got hurt in her place. Playtime resulted in many toys getting thrown around, snack time was always a mess, and bath time was filled with soap-filled hallways and slippery floors. Currently, Unikitty was napping peacefully in a pink crib that was being rocked by a tired Puppycorn, "Who knew being a big bro was such hard work?" he said.
"Honestly, I liked her better when she was older." Hawkodile said.
"That's because the both of you never had to take of her at this age." Richard said while covering them both with a blanket, "If you need anything, I have some unidentifiable stains to clean up." Richard then floated off to the kitchen while the three of them napped.
At the same time, Master Frown was sneaking up to the castle, a case of stink bombs in his hands, "This is perfect, I get half off stink bombs, and I get to ruin someone's day. Everything is coming up Frown." he said as he prepared to throw a stink bomb into the castle window. Before he did so, he got a peek at what was happening inside, Hawkodile and Puppycorn sleeping on the couch next to a pink crib, "Did they start babysitting now?" the Doom Lord asked himself before he snuck his way into the castle. He was now able to get a good look at the now infant Unikitty, still fast asleep, "New idea." he said to himself in a sinister manner.
Puppycorn woke up with a big yawn before checking up on his baby sister, "Alright sis, time to-" he started to say before looking in the crib to find it empty. This made him scream, which woke up Hawkodile and made Richard and Dr. Fox rush into the room.
"What happened?" Richard asked.
"Unikitty's gone!" Puppycorn said.
"Oh no, if we don't find her soon, something terrible might happen! Call the police! Call the army! Call the national guard!" Dr. Fox shouted while panicking.
Hawkodile then looked into the crib and found a note inside, "We don't have to look far." he said while picking it up and handing it to Richard.
"'If you want your princess back, allow me to roam free and cause misery. Signed, Master Frown. P.S. Mwahahahahahaha. P.P.S. Rate my evil laugh from one to five.'" Richard read.
"So he thinks he can just steal Unikitty away from us, huh? I say we show him what happens to people who steal babies." Dr. Fox while getting out a flamethrower.
"Come on guys! Let's go save our princess!" Hawkodile said while doing a dramatic point.
"Yeah! ...Right after I figure out how to rate his laugh." Puppycorn said while staring confusedly at the letter.
Back in Frown Town, Master Frown was staring out his apartment window, keeping a lookout for the gang, "Should be here any minute now." he muttered.
In Brock's bedroom, he was currently reading a story to Unikitty, "And then the littlest elf said..."
"Brock! Are you reading her a story?" Master Frown asked.
"Uh, no I was just... tormenting her with a boring history book." Brock said before holding up a textbook.
"You see Brock, the whole point of a ransom is-" Master Frown started to say before he was interrupted by a voice outside.
"We have the apartment surrounded! Come out with the princess in hand!" It was Hawkodile, holding a megaphone while Puppycorn, Dr. Fox, and Richard all held various weapons.
Master Frown opened the door and called out to them, "Don't come any closer! Or else Brock will intensify her torture!" In reality, Brock was merely tickling Unikitty while she giggled, "Dude, you're embarrassing me here." the Doom Lord said.
"Master Frown, you have two options: number one, you hand over Unikitty and we'll leave quietly. Number two, experience a very unpleasant full-body massage, courtesy of Hawkodile!" Dr. Fox said through the megaphone while Hawkodile was fitting some brass knuckles on his hands.
"I'll take option three, I destroy all of you right here and now! Brock, I'm going out for a while!" Master Frown said.
"Shh... she's sleeping." Brock shushed as Unikitty slept on a blanket.
Master Frown groaned in annoyance before jumping into his car down below and activating the mech feature. A big battle ensued, with Frown using the various weapons on his mech and the gang using their weapons. Puppycorn used a laser sword, Dr. Fox used twin flamethrowers, Hawkodile used a large hammer, and Richard used a weaponized feather duster. Master Frown proved to be stronger however, and beat away the gang with his mech, "Well, looks like you have not choice but to surrender." he said.
"Dream on, bingleberry!" Puppycorn said.
"Alright then, maybe you need more-" Master Frown started to say until Unikitty suddenly flew up to his mech and started cuddling it, "Brock, I thought you were watching her!"
"Babies need fresh air, man." Brock said.
"Argh! Get off!" Master Frown said as he tried to shake Unikitty off of him, only for her to hold firm. She may not have fallen off, but her pacifier was flung out of her grip and onto the ground, where it was crushed by Frown's mech.
"Ooh, he shouldn't have done that." Puppycorn said.
Unikitty flew down and observed the broken pieces of her pacifier. As expected, she started to pout with and angry face, "Oh what, gonna start crying now?" Master Frown mocked.
"Frown, I would start backing away really slowly if I were you." Dr. Fox advised.
"What's she gonna do, throw a tantrum?" the Doom Lord asked. He couldn't be anymore right, for Unikitty's fur had turned completely red and was on the verge of blowing. She then let out a loud scream and started chasing Master Frown. He yelled in fear as Unikitty chased him up and down the street. Her friends watched as Frown's mech was destroyed and he was no being used as Unikitty's punching bag, "Please, I'll stop bugging you guys if you get her off! Ow!" Frown screamed as he easily beaten up by the raging infant.
"All we needed to hear." Richard said before pulling out a spare pacifier and popping it into Unikitty's mouth, calming her down instantly, "Always keep a spare one." he said while picking her up.
"Come on, let's change her back." Dr. Fox said before they started off home.
Brock went to check on his roommate, "Dude, are you alright?" he asked.
"I... hate... babies..." the Doom Lord said before he passed out.
Back at the lab, Dr. Fox brought over the reddish serum that will turn Unikitty back. "Alright, here goes." she said before pouring a drop into Unikitty's mouth, causing her turn back into her normal self.
"Oh Doc, there you are! That lemonade was awesome, I felt so young while drinking it." Unikitty said. She seemed to have little memory of being turned into a baby.
"Glad you liked it. Now then, how about some celebratory fruit punch?" Dr. Fox said while pulling out a tray of punch.
"Alright!" Puppycorn said while grabbing the serum that Dr. Fox still held in her paw.
"Puppycorn, wait!" Dr. Fox said, but it was already too late as Puppycorn already chugged the whole thing down. The result was him becoming old, complete with wrinkling skin, a long grey beard, and a cane.
"Doc, please label your serums." Richard said.
"Yeah. little missy! Listen to your elders! Ow, my back!" Puppycorn shouted.