An engineer, Christopher Pelley, loses his eyesight in an accident but is due to have an operation to restore hie sight. One night he goes to a friend's house but the driver drops him at the wrong address by mistake. Pelley goes inside and discovers a body, as well as a ring, on the floor but the three killers, who are still in the house, decide to simply knock him out once they realise he is blind and cannot identify them. When Pelley comes round the police investigate his story but cannot locate the house or body, so after he regains his eyesight after the operation he decides to try to solve the mystery. He returns to the house to find Patricia Dale living there with her father and from a photo on the piano he realises that the ringbelongs to her brother, Norman, who is presumed dead after a plane crash a year before. Patricia agrees to investigate the mystery with Pelley, and they speak to Norman's friend Chalky, who was with Edward the night he was presumed to have died. Chalky gives them a couple of leads, and when Pelley follows up one at a travel agency he meets GuySinclair who works there and whom Pelly recognises as one of the three men who knocked him out by his voice. It becomes clear that the three men - Sinclair, a thug called Mickey and their leader, Otto - are involved in a smuggling ring, and Pelley manages to get hold of a book which, although in code, incriminates all three men in the smuggling racket. Pelley tracks the crooks down to an isolated house, The Grange, but is caught by Mickey and held prisoner in the house but manages to escape with the help of Lila, a girlfriend of Norman's. He enlists Chalky's help, and they go to see Lila, who has information for them, but she is killed by Mickey before they can speak to her. Patricia disappears after receiving a message asking her to meet someone at midday, whilst Pelley realises that Chalky has been working with the gang all the time, but he is killed by mistake by the gang instead of Pelley. Pelley then goes to find Patricia after telling her father to contact the police, and he finds her being held hostage at The Grange. It then transpires that her brother Norman is alive and is actually the gang's ringleader who faked his own death to evade arrest; the body Pelley stumbled over in the house was that of a customs investigator. Pelley manages to foil the gang and Norman falls to his death trying to escape from Pelley and the police, and Pelley and Patrica leave hand in hand.
