- Although the police have termed her mother's death a suicide, a teenage girl believes her step-father murdered her.
- Paul Decker murders his wife in her Italian villa by drugging her milk and asphyxiating her by gas. He cleverly locks the bedroom from the inside and hides inside a trapdoor in the floor until after the body is discovered by servants. He uses a scuba snorkel connected to tubes on the outside to breathe during the ordeal. Decker's stepdaughter Candy suspects him immediately, especially since no suicide note was found. She also is convinced that he murdered her father years before, but her accusations fall on deaf ears. The ruthless Decker even poisons the family spaniel when the pet takes too great an interest in the mask and realizes he will ultimately have to get rid of Candy too.—duke1029@aol.com
- In his house near the Italy/France boarder, Paul Decker [Peter Van Eyck] seals the windows and doors of a room with tape, attaches long rubber tubes to pipes that lead outside under the floorboards, and turns off the gas lights. His wife is sleeping on the couch. He turns the gas back on and puts on a diving mask with the rubber tubes attached to the snorkels to allow him to breathe while the gas asphyxiates his wife. When the servants [Marie Burke and Henri Vidon] arrive the next morning he opens a trapdoor in the floor and hides under the floorboards. The servants smell the gas and break down the door but Mrs Decker is dead.
The police inspector [Gregoire Aslan] and British consulate official Wilson [William Franklyn] believe it is suicide because the doors were locked from the inside and Paul is apparently away in France writing for a few days. However, Mrs Decker's daughter Candy believes her step-father Paul has murdered her and believes he murdered her real father a few years previously when he drowned during a boat trip. After everyone has left, Paul climbs out of his hiding place and leaves.
The next morning the police collect a letter delivered to the house apparently from Paul in France to say he is returning. Candy's governess Jean Edwards [Betta St. John] returns to the house to meet him and they return together to Candy at a hotel. Since her mother left no note, Candy is still convinced Paul is responsible for her death.
Candy visits the police inspector to try and convince him Paul murdered her mother. The inspector explains the only way to do that was for Paul to be invisible in the room and not breathing the gas. As Candy returns to the hotel she sees a poster for an underwater diver and realises someone could breathe for a long time with diving equipment. At the hotel Jean explains they will soon be leaving for America. Candy realises that if Paul had been in France, his passport would be stamped with the dates of his boarder entries and exits. Candy searches Paul's room for his passport. She finds the diving mask but Paul returns as she finds his passport. He shows her the stamp in his passport that clearly shows he returned to Italy the day after the death of Mrs Decker. Candy's dog Toto will not leave the diving mask alone so after Candy has left his room, Paul gives the dog a pill to kill it.
Candy tells Jean her mother hated the house but Paul would not let her change it, including changing the gas to electric. She accuses Paul of killing the dog and threatens to kill him.
When Jean and Paul go for a walk that evening Paul expresses his affection for Jean. He also expresses his concerns about Candy's psychological state of mind in order to distract Candy's accusations away from him. Meanwhile Candy sneaks back to search the room where her mother died. However, she is found there by Paul and Jean before she discovers anything.
At the beach the next day, Candy sees a man using a snorkel while swimming and asks Paul if she can borrow his. At first he denies he has one but when Candy persists she saw one in his hotel room, he reluctantly agrees. Candy goes for a swim but when she gets out of her depth Paul swims after her. When Paul reaches her he tries to push her under at first, but as Jean swims out too he helps Candy back to the beach. Candy accuses Paul of trying to kill her but Jean doesn't believe her, saying Paul rescued her.
That evening Paul leaves for France under the pretence it will be better if he is away from Candy. From a hotel just past the border he uses the snorkel to swim back past the border into Italy. From his house he telephones Candy, pretending to be an Italian police officer in order to persuade Candy to come to the house to meet the inspector. He seals the windows again with tape and makes some warm milk for Candy, into which he puts some sedative. When Candy arrives Paul pretends he has found a letter from her mother and is waiting for the inspector to arrive. Paul reads the letter which says Mrs Decker was terminally ill and wished to end her life. Candy is upset so Paul gives her the milk to drink to comfort her. She sees the letter is actually a blank piece of paper and the windows are sealed but passes out before she can escape. Paul lays her on the couch and seals the door, turns the gas on and puts on his mask and snorkels. However, Jean and Wilson arrive looking for Candy so Paul hides under the floorboards again. They save Candy from asphyxiation and Candy tries to convince them Paul tried to kill her but they think she has attempted suicide because of her mental state following the death of her mother. They reluctantly agree to at least look for where Paul might be hiding but there is nowhere. Candy finally relents and agrees with them she must be wrong and it must all have been in her imagination. She promises not to say anything further about Paul trying to kill her. During the search, Jean and Wilson moved a heavy cabinet onto the trap door in the floorboards, trapping Paul underneath. As they leave the house Candy runs back in for one last look. Paul begs her to let him out but she thinks his voice is her imagination and leaves him there.
On their way back through the town, Candy goes into the police station to tell the inspector she knows how Paul did it, and to look under the floor of the house.
Contribute to this page
Suggest an edit or add missing content