Aiden is a young, budding scientist who regularly babysits little Fifi when her parents are out for the day. He attempts to work on multiple serums, recording data, as she crawls around on the floor playing with her teddy and Barbie, often interrupting his work. Confident that little Fifi will be okay, Aiden tells her that he needs to go to the bathroom, and that he will be right back.
He leaves the room, and Fifi looks around, sucking on her pacifier. Eager to satisfy her need to put anything and everything in her mouth, she looks up at Aiden’s serum bottle. She crawls to the desk, and grabs the bottle, thinking it’s full of milk. She throws the pacifier out of her mouth, pushes the bottle in, and nibbles on the top, creating a small hole for the serum to leak out. Once she’s full, she throws the bottle onto the floor, and puts the pacifier back into her mouth.
After a few seconds, her eyes widen, and she gasps, dropping the pacifier onto the floor. She feels herself growing taller, and her shirt begins to rise with her new developing body. Suddenly her diaper rips at the side, and her shirt tears down the middle, exposing her new breasts. Her chest pops out and expands, becoming bigger and fuller, and she finds her hands clinging to them. Overwhelmed with the sensations occurring in her body, she moans as she explores herself for the first time. Her ass grows, and she smacks it, taken back by her sensitivity. She rubs her clit, and smiles at the pleasure it brings. She moves awkwardly, still trying to get used to her new legs, and continues to enjoy her newly developed body.
As she is discovering herself, Aiden comes back from the bathroom only to find Fifi as a full grown woman! He can’t help but watch for a second before saying, “Oh, fuck!” Fifi turns around to see Aiden standing in front of her, and she innocently says, “Hi! Do you… Do you wanna play with me? I’m playing with myself.” Aiden tries to resist, explaining that he needs to change her back before her parents return, but she continues, “…Okay, but can we… can we just play first? Can you touch me? I’ve never been touched before. Just touch me real quick…”
She grabs his hand, and unable to resist her beauty any longer, he lets her guide it onto her body. She makes him squeeze her full, perky chest, and then guides his fingers inside of her pussy. Fifi moans from pleasure, and continues to tempt Aiden with her new body. “Can you feel how wet I am?… Here, I have an idea. Maybe you could lick me. Just real quick… You know, before my parents come back. Come on, no one’s ever touched me with their tongue before. You’d be the first one…” She moves her leg onto the chair, and Aiden gets underneath her to lick her pussy. He reminds her that they need to change her back, but she distracts him, and eventually, she has him fucking her.
Filled with pleasure, she cums, and tells Aiden to cum onto her face. He releases his huge load all over, and she smiles as he tries to hand her a reverse serum. She is quickly distracted by the knocking at the door, and gets up to greet her parents. Panicked, Aiden tries to hand her the serum once again, but she excitedly answers the door, “Mommy, I’m all grown up! Look at me! …and there’s cum all over my face!”