Everything was a nice day, at the chercher Guard Successor Foundation, and Natsuki was touching buttons on inventions, as she was told not to. Then, she was getting bored, and left the room,
Later, when Masumi and the gang entered, They were shocked/appalled.

Masumi: what happened???!!!
Sakura: (sigh) Natsuki, happened.
All: NATSUKI!!!!!

Later That Day,
A new invention arrived,
Mr Voice: Everyone, gather around behold the new personality changer, it can change any personality, par pressing the blue button. and when toi press the button, it sprays a person.
Souta: So can it work on anyone, including Natsuki.
Mr Voice: Yes, yes it can.

Hours Later,
Natsuki was noticing the invention, she was so curious about it. she saw a blue button, and it sprayed her.
When she gotten sprayed, she began to develop the mind of a 1 an old (as she usually acts like), she sucked her thumb. and then wet herself. Masumi then approached her.
Masumi: salut Natuski, i-----, Natuski did toi just wet yourself.
Natsuki: (baby talk) Yes.
Natsuki: (baby talk) Can toi change me??
Masumi: (sigh)

Masumi then picked Natuski up, got a table, and her on it. he removed her panties, and shirt. revealing her pussy. and he then put a diaper on her. and she then put on her skirt, under her diaper.

Natsuki: (baby talk) can toi pick me up, now.
Masumi: yes
(Natsuki then took off her shirt, revealing her bare chest, as well, as her jupe and hopped on Masumi's back)