"Actually, imma let you stay as a big girl." Hollie says, running over to her little sister and hugging her. "A five-year-old who still has to wear diapers is so cute!" She exclaims, patting her on the head.
Hollie attempts to lift Jeff up off her feet, but finds herself to be too short to do so. She smirks at her sister, and turns her attention back to the computer.
"You know, Jeff. I've always kind of wondered why I was so short. Then just a bit ago while you were having a bath, I saw your computer, and saw that his program's history box says you shrank me just earlier today!" Hollie looks at her sister and shakes her head disapprovingly--though with a humorous, mocking tint.
Hollie grabs the mouse and hits "Undo" on the transformation that had shrank her down. Immediately, she and her clothes re-grow to their original 4'8. Her memories are corrected a moment later.
"Jeez! That's weeeeeirddd!" Hollie leans against the desk and rubs her forehead. "This contraption really messed with my mind!" She looks down at Jeff and points a judgmental finger at her.
"You were going to make me be a tiny midget for the rest of my life, without even asking me!" She proclaims, still with a bit of humor in her tone, but legitimately offended at the same time.
Jeff looks down at her feet and twiddles her thumbs together.
"I was... I was... I wasn't..." She stutters, finding she didn't have the confidence to speak up for herself.
"Your name is Jenny now, okay Jenny?" Hollie says, putting an encouraging hand on her shoulder.
Jeff cocks her head up to her sister and gives her a teary, remorseful glare.
"....okay...." Jenny says, just before bursting into high-pitched bawling.
Hollie leans down, reaches over and gives her a hug; fully featured with head-scratching and back-rubbing. She explains to her little sister that, because she is genuinely sorry for what she did, she is not going to alter her memories; and will merely leave her as an incontinent five-year-old girl for now.
Next, Hollie decided to change Jenny's diaper. Jenny was very resistant at first; feeling uncomfortable being seen naked, especially now that her body has just been transformed; but Hollie was able to coax her into calming down after 15 minutes or so. As Jenny felt her sensitive areas getting cleaned up by her sister, she found herself finding surprising peace and tranquility in her current state.
----
Later that day when their parents got home, Hollie had a pretty difficult time explaining the Chronivac to them, and justifying to them why she had turned their son into a little girl, but when Jenny expressed pleasure with her new form, the mom and dad simply shrugged and gave it their approval.
Explaining it to Jenny's friends the next day wasn't nearly as intense, but it definitely made them more confused. They hanged out with Jenny in her room like they always did, and it was true that Jenny still mostly spoke and acted like her original self, but it just felt really off that a small group of teenage boys were snacking and gaming with a five-year-old girl.
Awkwarder still was the moment when Jenny suddenly smelled of poop, then casually stood up and walked out of the room calling for her sister, and then came back seven minutes later. No one had told them Jenny was diaper dependent, but given how they were poking out the top of her pants, and given the crinkly sound when she walks, they definitely assumed such to be the case.
----
Monday came the next morning, and their parents had decided--after testing to find Jenny still fully retained her 10th grade education--that she didn't need to go to kindergarten. On the same token however, she would need to keep up with the schoolwork she already had to deal with. Her school offered an online version of its courses, so they had her pick that up. This left Jenny without having to worry about high school BS, but still having to deal with high school education. The motivation to get all of her work done while being in her room was difficult to obtain at first, but she got the hang of it after a few days.
After a week and a half, Jenny's friends stopped coming over all the time, and she didn't mind. They had both been feeling distant from one another. Jenny found herself wanting to associate with other little girls; she found herself looking up to her sister more and more as a legitimate older sibling. She stopped feeling uncomfortable with wearing and using diapers, and even with Hollie changing her. Before long, being seen in the nude by her sister--and even by her mom and dad--felt perfectly normal. Hollie also gave Jenny her baths; sometimes they bathed together. As a teenage boy, Jenny would have been horrified to see Hollie naked, but in her current state, it only made her look up to Hollie as a "big kid", with a body that she hopes to have one day.