Bank Holiday weekend. Sunrise on a secluded Welsh beach and Beatrice Stubbs takes some innocent snaps. The scene contains more than just cliffs and seagulls, and someone wants those pictures destroyed. But Beatrice's mind is on other things. Assigned to the London Transport Police, she's pursuing the Finsbury Park Flasher, trying to pre-empt a serious sexual offence.

While Beatrice is distracted, neighbour Adrian and companion Matthew decide to play Poirot, and investigate the mystery of the disappearing photographs. Amateur detectives and professional criminals are a dangerous mix....