Four more adventures featuring Agatha Christie's light-hearted 1920s sleuthing duo, Tommy and Tuppence Beresford (James Warwick and Francesca Annis). In 'The Man in the Mist', a beautiful actress, Gilda Glen (Linda Marlowe), sends a note to Tommy asking for his help. However, when the Beresfords go to the agreed meeting place, they find Gilda dead... In 'The Unbreakable Alibi', the duo are asked to help a wealthy man win a bet with a beautiful art journalist: if he wins he will marry her, if he loses he will never see her again. In 'The Case of the Missing Lady', a polar explorer (Jonathan Newth) asks the sleuthing duo to help him find his missing fiancée, who vanished without trace while he was away on his latest Arctic expedition. Finally, in 'The Crackler', Scotland Yard call Tommy and Tuppence in to help with a high society fraud case.