Skip to Main Content

About The Book

The Sanctuary meets Shutter Island in this high-concept psychological thriller from the critically acclaimed author of The Sisterhood.

Birds of a feather

A group of teenagers jump off a train platform intentionally into the path of an arriving train.
The lone survivor, Charlie, cannot recall the incident, but is adamant that she and her friends weren’t suicidal.

Flock together . . .

Her mother, Jo, is desperate for answers. When she’s approached by Nathalie Bergstedt, the Director of the Arbor Institute, a government-affiliated research institute who are investigating the rise of ‘flock’ behaviour phenomena – where people are banding together to self-destruct – she agrees to take Charlie there.

But never underestimate,

At the Arbor Institute, Charlie is told that she’s at risk of ‘re-flocking’ and if she does, she will likely die. But when another flock-survivor disappears and Charlie discovers that she’s being watched, she realises that not everything is as it seems at the Institute. But as everyone knows, nature is red in tooth and claw and you should never corner a wounded animal.

The instinct to survive. . .

About The Author

Katherine Bradley enjoyed a twenty-year career managing services for homeless people in Brighton, before retraining as a teacher. She now teaches English in a secondary school academy, finding time to also teach creative writing to adults. She holds a first-class degree in English Literature, in addition to qualifications in teaching, creative writing and coaching. As Kate Bradley, she has published two suspense thrillers –​ To Keep You Safe (2020) and What I Did (2021). Her work has been described as 'addictive, original and brilliantly twisty' by T. M. Logan and 'heart-stopping' by David Nicholls. Katherine lives near Brighton with her family. Follow her on Twitter @kate_bradley

Product Details

  • Publisher: Simon & Schuster UK (February 26, 2026)
  • Length: 400 pages
  • ISBN13: 9781398514300

Browse Related Books

Resources and Downloads

High Resolution Images

More books from this author: Katherine Bradley