Once upon a time the Earth started spinning more slowly, which messed up food supplies, sleep schedules, and lighting. Everyone panicked. This little girl named Julia lost her one friend when she moved to Utah, and afterwards Julia is pretty well isolated from other people.
A few chapters from the end this boy that she likes suddenly starts being nice to her, and they hang out all the time. Well, until he gets sick, and moves to Mexico.
This book is an all-around bummer with no conclusion. No thank you.
Other plot happenings:
Grandpa dies in his fallout shelter, but no one knows where he is for a month.
A friend runs away to a 'real time' colony, where they reject the rules of the clock.
Julia steals a bra.
Julia's dad cheats on Julia's mom with the neighbor.
And that's really about it.