Frank Jessup, an ambulance driver with ambitions of opening his own garage, becomes entangled in the tumultuous and seductive world of Diane Tremayne, a mysterious young woman living in a wealthy Los Angeles neighborhood. One night, while responding to a suspected gas leak accident at the Tremayne estate, Frank meets Diane, whose alluring charm quickly captivates him. Diane appears to be trapped in an oppressive environment under the thumb of her stepmother, Catherine, whom she resents. As Frank grows closer to Diane, he becomes further embroiled in the domestic tensions and dark secrets that permeate the Tremayne household. His budding relationship with Diane places him at odds with his sensible girlfriend, Mary Wilton, who warns him against getting too involved.

Drawn by Diane's allure and promises of wealth and success, Frank is pulled deeper into a web of deceit and manipulation. Diane's infatuation with Frank intensifies, leading her to propose a drastic solution to escape her perceived entrapment. Frank finds himself caught in Diane’s machinations, questioning his moral compass as he grapples with his feelings for both Diane and Mary. As the narrative unfolds, the line between love and obsession blurs, with mounting tension leading to unforeseen consequences. The story navigates themes of love, ambition, and the destructive power of obsession, bringing Frank to face the stark reality of his choices amidst Diane’s enigmatic and precarious ideals.