Notorious womanizer Michael James, Peter O'Toole, wants to be faithful to his fiancée Carole Werner, Romy Schneider, but almost every woman he meets is drawn to him. Among them is Liz Bien, Paula Prentiss, a neurotic exotic dancer, and Rita, Ursula Andress, a parachutist who accidentally lands in his car. His psychoanalyst, Dr. Fritz Fassbender, Peter Sellers, struggles to help, since he himself is pursuing patient Renée Lefebvre, Capucine, who longs for Michael. Carole, meanwhile, decides to provoke jealousy by flirting with his nervous friend Victor Shakapopulis, Woody Allen. Victor, awkward in romance, is nonetheless drawn into Carole’s feigned interest.
Fassbender continues his group therapy with neurotics and obsessives, and the sessions grow increasingly strange—one even features an indoor cricket match. Michael envisions a delirious fantasy in which every woman he has known stacks the attention on him, each listing the places they had sex. One night, Fassbender heads to the Seine, rows out in a boat filled with kerosene, and wraps himself in the Norwegian flag, preparing to die in a Viking funeral. Victor sits nearby at a small dining table and asks what he is doing; distracted, Fassbender abandons the suicide plan and begins dispensing advice to Victor. The twist reveals that Fassbender, despite his professional aura, is married with three children, adding a layer of irony to his relentless pursuit of romance.
Meanwhile Carole’s plan seems to work, and Michael agrees to marry within the week. She moves in with him, but fidelity proves elusive. When Liz introduces herself as Michael’s fiancée, Carole grows indignant. At the same time, Rita parachutes into Michael’s open-top sports car and the pair check into a small country hotel, though he resists her advances. Gradually, all participants converge on the hotel—Carole’s parents wander the corridors, and Michael makes his rounds from room to room. A rumor spreads that an orgy is taking place, drawing in side characters such as the petrol station attendant. Carole arrives to see Michael’s room, and as they converse, the others chase each other through the background. Fassbender’s overbearing wife, Anna Fassbender, Eddra Gale, tracks him down in the melee.
Everyone ends up in Michael’s room with many of the women half-naked, as the police line forms outside. Anna, dressed as a valkyrie and armed with a spear, leads the group through the police cordon, and they escape to a go-kart circuit. They race away, then divert to a farmyard, slip through narrow village streets on the go-karts, and return to the circuit. In a later twist, the Mayor, Le Maire Richard Saint-Bris, marries Michael and Carole in a civil ceremony, but the moment of signing the marriage certificate is overshadowed when Michael callously greets the young registrar with “Pussycat,” infuriating Carole. As the dust settles, Fassbender reappears, and the therapist makes a final, if uncertain, effort to court Carole instead.
