A further exploit of the Crabbe and Crabbe detective agency, set in 1920s England. The partners of the firm have unusual qualifications for detectives. Both in their twenties, Melpomene is a social anthropologist, and Alexander is a solicitor, a combination that brings fresh approaches to a sometimes jaded profession, benefitting from collaboration with police colleagues in London. This, their latest case, begins with an approach from a doctor, concerned about unexplained happenings at his hospital. The Crabbes begin following up some of his enquiries and find evidence of serious difficulties and wrongdoing by certain pharmaceutical suppliers, with consequences that reach further than the hospital.