The Scarlet Hour (1956)

In Los Angeles, salesman E.V. 'Marsh' Marshall works for wealthy real-estate developer Ralph Nevins. In his spare time he sleeps with his boss' wife, Pauline Nevins. She was saved from poverty by Ralph when they married but Ralph is much older than her and she hates him. Of course, she loves his money and that's why she doesn't leave him for the much younger office hunk Marsh. Despite the secret affair, Marsh respects his boss who gives him promotions and praises. Nevertheless, he would elope with his boss' wife but she wouldn't hear of it. Love is one thing but a return to a life without luxuries is another. At the office, Ralph Nevins' secretary, young Kathy Stevens, secretly loves office beau Marsh but she is too shy to reveal her feelings. She would later play a crucial role in a murder investigation involving the main characters. During one of their secret interludes under the moon, Marsh and Pauline Nevins witness a discussion between three shady men who are planning to steal precious jewels from a nearby mansion belonging to a certain Dr. Sam Lynbury and his wife. The robbery is planned for the following week when the mansion residents are away on vacation. Overhearing the thieves' plan, Pauline and Marsh figure a plan of their own. After the robbery, Marsh could ambush the thieves at gunpoint and rob them of their loot. This loot would provide Marsh and Pauline with enough money to elope far away from Pauline's husband. Marsh is a bit reluctant to commit a crime, at first. But Pauline persuades him to do it. However, plans have a tendency to go awry. To make matters worse, Pauline's husband starts being jealous and suspicious of her secretive leisurely activities. He decides to tail his wife to see if she's cheating on him. As a precaution, he takes his .22 caliber pistol with him. By coincidence, the night he chooses to tail her is the same night when she and Marsh meet at Dr. Lynbury's mansion to rob the thieves who, after breaking the safe, have the jewels.