In the midst of a volatile and bickering marriage in "Swinging London," wealthy architect Robert Blakeley (Michael Caine) begins a passionate affair with Stella (Susannah York), a gentle and refined boutique owner. His wife, the flamboyant and acerbic Zee (Elizabeth Taylor), refuses to go quietly. Driven by a mix of jealousy and a refusal to lose her "possession," Zee launches a psychological war to sabotage the romance. The conflict eventually spirals into a provocative and cynical power struggle that culminates in an unexpected sexual confrontation, blurring the lines of the original love triangle.