A charming young man worms his way into a wealthy woman's household, then reveals a deadly secret.

In a small English village, the police drag the river, searching for the body of Mrs. Shellbrook, who has been missing for several days. Meanwhile, at the home of Mrs. Bramson, a churlish, elderly woman who pretends to need a wheelchair, the maid Dora tells her mistress that her Irish boyfriend, Danny, works for Mrs. Shellbrook. Danny, who knows that Mrs. Bramson is a hypochondriac and only pretends to need a wheelchair, is very solicitous toward her. He tells her that she reminds him of his mother, then says that he loves Dora and would marry her if he had a better job. Mrs. Bramson's niece and companion, Olivia Grayne, is suspicious of Danny, but Mrs. Bramson stubbornly refuses to listen to her. Soon Mrs. Bramson's attorney, Justin Laurie, arrives to give Mrs. Bramson some money, and warns her not to keep much cash around the cottage, but she is unconcerned. Meanwhile, Justin, who is in love with Olivia, asks her to marry him, but she refuses because she yearns for something "romantic" to happen. After Justin leaves, Mrs. Bramson puts money into her safe and is secretly observed by Danny. A short time later, Danny purchases a scarf in the village and gives it to Mrs. Bramson, saying that it belonged to his mother. Olivia, who sees the price tag on the scarf, says nothing as she and Danny secretly eye each other, acknowledging their mutual attraction. Soon Dora discovers Mrs. Shellbrook's decapitated body. Though Olivia accuses Danny of the murder, he denies it and says that he merely fantasizes and pretends to be mysterious. Though she is still fascinated by him, Olivia is now certain that Danny is the murderer. Mrs. Bramson dismisses her niece's accusations because she has grown very found of the attentive Danny. When police inspector Belsize comes, he searches Danny's room and find a large, locked hatbox. He is just about to open it when Olivia impulsively grabs the box and says that it is hers. After Belsize leaves, Danny faints, and at dinner that night both he and Olivia are ill at ease. Olivia soon calls Justin and asks if she can stay with him, then begs Mrs. Bramson to come along, but she refuses. Even when the maids also leave the cottage, Mrs. Bramson feels safe enough to stay while Danny, who has cut the telephone wires, walks the maids part way to the village. Alone in her drawing room, Mrs. Bramson hears noises and becomes frightened. When she screams for Danny, he comes in and calms her down by giving her something to drink and lulling her to sleep. Then, when he is certain that she is asleep, he starts to smother her. She begins to wake up, but it is too late, and Danny kills her. He then robs the safe, after which Olivia returns and sees what has happened. She admits that she was attracted to him, but says that that is over. He threatens to kill her, too, to cover up his crimes, but just then the police, who were called by Justin when he could not reach Olivia by phone, arrive and arrest Danny. As he leaves, Danny says "I'll hang in the end, but they'll get their money's worth worth at the trial." Finally, as Danny is taken away, Justin and Olivia embrace.