It is May 1971, and the Cambridgeshire countryside is bursting into summer. Archdeacon Sidney Chambers is walking in a bluebell wood with his daughter Anna and their ageing Labrador Byron when they stumble upon a body. Plunged into another murder investigation, Sidney discovers a world of hippies and psychedelic plants, where permissive behaviour seems to hide something darker. This is the first of many disturbing secrets that Sidney unearths beneath the tranquil surface of the diocese: a celebrated photographer is accused of rape; a priceless religious text vanishes from a Cambridge college; the authentication of a lost masterpiece proves a slippery business; and Sidney's own nephew goes missing...