Secret place. Tana French. 2015.

‘I know who killed him’.

The anonymous message is written on a photograph of Chris Harper, a boy found murdered a year ago in the grounds of an exclusive girls’ boarding school.

Detective Stephen Moran knows it could be his longed-for passport to the Dublin Murder Squad and he leaps at the chance of joining Detective Antoinette Conway to visit the school and re-open the case.

But in this claustrophobic, privileged world, every step they take leads back to a place more savage and mysterious than they imagine - to the ties that bound a group of adolescent girls to Chris Harper and to each other, to their friendships, their feuds and their deepest, most dangerous secrets.