Imaginary Girls by Nova Ren Suma

8603765 Imaginary Girls is a deliciously eerie Young Adult novel about sisters, a strange town in New York, and drowned girls who simply won't stay dead.

Chloe was practically raised by her stunning, compelling, adored older sister, Ruby. Nobody can say no to Ruby. No one would want to. Everyone loves her, and wants to be near her. But the only person Ruby loves, or even cares about, is her baby sister. Yet when Chloe discovers the body of her dead classmate in the reservoir, she moves away to live with her father, and doesn't hear a single word from her sister for two whole years. Until one summer, when Ruby appears on her doorstep, insisting that if she comes home, things will be exactly as they were before. Chloe just has to follow a few simple rules: don't leave the town lines. Don't go near the reservoir. And don't question how a girl who she saw dead in the water is suddenly walking around as though nothing happened at all.

The novel starts somewhat slow, and I simply couldn't understand why Chloe was such a doormat when it came to her sister, or why everyone loved a girl who was clearly pretty horrible and self-absorbed. But the book gets better. Oh, it gets so much better. It's a slow build, but by the time you reach the midway point, it's gained so much spine-chilling momentum that it's impossible to put down. Not because it's particularly full of action or plot, mind. Not a lot really happens in the book. But as the layers are pulled back, and you discover more and more about Ruby, and the town that lies at the bottom of the reservoir, the book weaves a compelling spell. It's somewhat supernatural, although it doesn't make clear exactly what is going on. It's all questions and suppositions and "I wonder if...", and if you love lyrical prose and supernatural mysteries, the sort that make you feel nervous and exposed in a subtle, indefinable way, this is an excellent novel to get lost in.