Ireland, AD 671. Cashel is preparing for its great summer fair when a travelling wagon catches fire at the edge of the gathering. The driver, apparently a woman disguised as a boy, is killed, and Eadulf discovers a second, decomposing body hidden among the cargo.
With merchants, entertainers and visitors arriving from across the kingdoms, Fidelma must identify two victims whose assumed identities were intended to prevent recognition. The investigation moves through the fair's temporary community and reveals fraud, corruption and a planned crime that depends on the confusion of the celebrations.