Tension

Lieutenant Collier Bonnabel explains on camera that he solves cases by applying pressure to suspects until they snap under the tension. He cites a murder case involving Warren Quimby to illustrate how a suspect can crack, setting the tone for the investigation that follows.

In flashback, Quimby is the night manager of a drugstore and married to Claire, who is openly unfaithful. She leaves him for the wealthy Barney Deager, leaving Quimby humiliated and alone.

Quimby goes to Deager's beachfront house to plead with Claire to come back, but the confrontation turns rough. Deager beats him up, leaving Quimby battered and publicly humiliated.

Quimby vents to his sympathetic employee Freddie about what happened, and Freddie remarks that, if it were him, he would have killed the man. The remark plants the seed for Quimby's drastic later changes.

To escape humiliation, Quimby constructs a new identity as cosmetics salesman Paul Sothern. He buys contact lenses and flashier clothes and rents a new apartment to start fresh.

Quimby, now Paul Sothern, begins dating his sweet neighbor, Mary Chanler. Their relationship offers him genuine affection and a link to his new identity as he settles into his new life.

Quimby goes to Deager's house with an intent to kill him in his sleep, but he realises Claire isn’t worth the plan. Deager awakens during the standoff, and Quimby mocks him, insinuating Claire’s infidelity even though she isn’t present.

Claire unexpectedly returns and tells Quimby that Deager has been shot. Bonnabel and Gonsales arrive to question them and realize Claire left the murder scene. She claims she visited as a day guest to swim, asserting they had been friends with Deager for years.

Mary goes to the Bureau of Missing Persons with a photo of Sothern, making it obvious that Sothern and Quimby are the same man. The officers, however, do not yet have the murder weapon to press the case.

The police arrest Quimby and question him about the murder, but his story is not believed. They press him to reveal the location of the gun, and he deflects, insisting they should ask Claire.

Bonnabel visits Claire and explains that they had to release Quimby due to insufficient evidence. He stresses that the gun could be the vital clue needed to convict him and hints at Claire's possible role in exposing the truth.

Claire retrieves the gun from its hiding place under a rock near the beach house and plants it in Sothern's apartment. Mary and then Quimby arrive, followed very shortly by the police, who are closing in on the case.

Mary and Quimby arrive just before the police, and Claire pretends to find the weapon under a chair cushion. Bonnabel explains that the furnishings had been replaced, exposing Claire's incriminating trick. Claire is arrested as the truth closes in.