- MC (boy) and his sister are on their last day of summer-camp
- sister invites 2 girls, she made friends with, over for an end-of-summer-camp sleepover
- the next day, MC wakes up as one of the girls
- after the panic for the 4 settled, they know that they all switched bodies. Brother to Girl B, Girl B to sister, sister to girl A and Girl A to brother.
- But they couldn't investigate this supernatural phenomenon because their parents picked them up before lunch.
- They weren't idiots and claimed outrageous impossible things and just hastily exchanged contact info. Apart from the sibling pair, they all lived in different states.
- after a mentally exhaustive day, they all fell asleep at "home"
- the next day, they awake ... at the summer-camp again but switched bodies to another round.
- The MC was now in his sister's body, sister to brother, girl B to girl A, girl A to girl B
- the day basically repeated himself, but the teenagers were in a different body.
- day 3, they awoke again at the summer-camp, the brother was in girl A, girl A to sister, sister to girl B, girl B to brother
- day 4, they awoke in the summer-camp again... in their own bodies
- day 5 MC wakes up as Girl B in her home.
- and round and round it goes.
- basically, they experience every day 4 times as the 4 different teenagers.
I first thought about not doing the "repeat the day as every character" but then I thought, this would be much cooler. Without the repeating days, they would only experience their real life every 4 days.
With repeating days, they would live all of the 4 timelines just in different bodies, making the bodies timeline their own. With all the internal and external drama it generates.