The Institute : Five students stepped in front of a train. Only one came back. But what happened on the platform was just the beginning. - Katherine Bradley

The Sanctuary meets Shutter Island in this chilling speculative thriller from the acclaimed author of The Sisterhood. BIRDS OF A FEATHER FLOCK TOGETHER. SOME FLY TO THEIR DEATHS. A group of students step off a platform into the path of an oncoming train. Only Billie survives. She remembers nothing. But she knows they weren't suicidal. At the secretive Arbor Institute, Billie is diagnosed with `flock phenomena': a terrifying impulse to self-destruct with the group. If it happens again, she'll die. Cut off from the world, watched at every turn, Billie begins to understand the truth:The Institute isn't trying to cure her. It's trying to contain her. But Billie isn't prey. She's the threat. `Brilliantly executed, alarming, deeply disturbing and worryingly believable!' Trevor Wood, author of The Inside Man`Thoughtful and compelling. Moving and memorable' Jo Furniss, author of Dead Mile