Following a string of successful performances along the west coast, the Moscardi Circus is travelling by train to Hexham on the Newcastle to Carlisle Railway for their next show. Yet a collision on the track with a couple of sleepers causes pandemonium. When the headless body of a woman is discovered in nearby woodland, Inspector Colbeck is desperate to lend assistance, however a reluctant Superintendent Tallis forbids him from doing so. Torn between his desire to detect and his duty as a father, Colbeck agrees, until contact from an old friend is made and Tallis relents. With the performers pointing fingers at both the competition and each other, the interference of locals concerned about the show's morality, and a planned takeover bid of the NCR, Colbeck has his work cut out trying to untangle the thread of events.