Mariru-chan is a modern girl with a stylish inner color. This is a documentary video in which a young girl navigator, who is not interested in wetting herself or diapers, calms her down, begs her, suggests her, and uses all sorts of tricks to turn her into a ``baby diaper girl.'' While drinking tea with a strong diuretic effect and answering questions about excretion, she can no longer hold back her urge to pee and wets herself in her clothes. She is forced to change into girls' underwear and wets herself again. Perhaps the suggestion from her older sister that ``adult wetting yourself is exciting because of the embarrassment'' worked, as there was a stain that was not pee on her pants... Mariru-chan is made to age even younger and this time she is made to wear a disposable diaper. And she urinates again. When cleaning up, she is found to have a slimy substance that is not pee, and is spanked on the buttocks. She masturbates in a disposable diaper in front of her older sister, who has given up on the fact that she is naughty. While sitting on her beloved stuffed toy's face and rubbing her crotch, she climaxes and wets herself. Mariru has become completely obedient. Next, she is made to wear a cloth diaper. It's a cloth diaper she's never seen before given her age, but it feels warm and comfortable on her bottom... and the baby powder smells nice too. She pees into the cloth diaper while enjoying the company of her now motherly older sister. She's now a fully grown baby!