A young woman (Jean Simmons) is convinced by her scheming and dangerous aunt (Sonia Dresdel) and uncle (Barry Jones) that she's losing her mind and in very delicate condition that requires their supervision which turns out to be more like manipulation, as they try to keep her as far away from outside human contact as possible. The only other person she sees is the estate caretaker, a lascivious character played by Maxwell Reed, whose caught the wayward eye of the middle-aged aunt. All of this, the aunt and the caretaker, the butterfly expert uncle who has a serious underside to him, and the susceptible niece in the middle, would have made for a darker and more sinister film. As it is, a frame-up for a murder sends Trevor Howard (a fired government secret service agent who took a job at the estate cataloging butterflies) and Simmons across the countryside escaping police, catching headlines of "Police Net Closing In" over her front page photo, hopping on buses, and winding up in Liverpool, where they meet some wonderfully cast characters, and finally face down the greedy and murderous aunt and uncle.