Hastings is invited by his friend Charles Arundel to be on hand when he attempts to break a water speed record on Lake Windermere, but his boat's engine fails. At a subsequent reception at the estate of Charles's wealthy aunt, Poirot and the other guests witness his refusal to continue funding Charles's expensive hobby, and he threatens her. Later, when she is nearly killed in a freak accident involving her pet fox terrier Bob, she confides in Poirot that she suspects a member of her family is trying to kill her to gain part of her estate. The detective will advise his greedy relatives and appoint a friend as the beneficiary. Despite this precaution, she dies abruptly under questionable circumstances, but the local authorities refuse to authorize an autopsy. Suspecting foul play, Poirot looks to her wits, as well as the dog Arundel, who remains a silent witness to the murder.