After a body is found on an Oxford tour bus, Lewis and Hathaway are led to Crevecoeur Hall, a sprawling Oxford estate where Hathaway spent much of his childhood.

When the master of a college is found dead at the foot of the observatory stairs, suspicion falls on all of the staff - from senior tutors right down to the scouts.

Lewis and Hathaway investigate the murder of a university friend of pathologist Laura Hobson. As more deaths occur, they realise that Laura's past may hold the key.