Sarah and Joy are sitting around talking about the good ol' days and how Joy used to be able to baby her little sister. It sounds so good to Joy, that she excuses herself to "go run some errands" but returns with some diapers and a binky.
Sarah is a little taken back by this. They were just talking about it, but she's now a big girl and doesn't need diapers. But Joy thinks it'll be a lot of fun and begs Sarah until she agrees. So Joy puts her little sister in a diaper, shoves a binky in her mouth and starts treating her like a little girl again.
Sarah doesn't take too long to get into it and started demanding something to drink. So Joy gets her some kool-aide but makes it a little too powdery and the little girl in Sarah reacts pretty badly to it. Joy fixes it and treats her like a little girl for a bit, but decides the little girl should only be wearing just her diaper. So she takes off all of Sarah's clothes and walks off to put them in her room.
While she's gone, Sarah crawls around a little bit and decides to have an "accident". When Joy returns, she's amused that her little sister just wet herself, but decides she needs a change and a nap.
A few days later Sarah comes home from school and runs into her big sisters room. Joy is annoyed her sister is bugging her until Sarah starts showing off her overly wet diaper. Sarah had so much fun the other day she's decided to keep up being a little girl and demands that her big sister change her diaper.