learns she has administered an undetectable poison to her father, to hasten her inheritance. He threatens to call the police, she reminds him of the money he will get from her. He reports the cause of death as stroke.

Cheryl meantime has rendezvoused with the blackmailer at Cooper's apartment, is talked into an affair in exchange for dropping the threat against her lover. After the lovemaking Larry taunts her, saying she's not worth the money. Lawyer for the estate (Alex Rocco) says reading of the Waterman will awaits arrival of the other sister Gail (Vicki Peters), who left home years before. She arrives with an older woman companion, Kate (Jacqueline Dalya), who makes their relationship clear.

At the reading of the will Victoria is thrown into a psychotic fury when she learns Gail inherits, while she receives only a small amount monthly. Carried to her room and given sedation, Cooper has the nurse stay with her, with orders to keep her locked in. Meantime, he courts Gail, really falling in love with her; they go to the beach, to a fair, and Kate in a huff, leaves for the East. Learning about Cooper and Gail, Victoria goes completely off balance. That night she appears so calm that Gail gives in to her request: the nurse is dismissed, the bedroom door left unlocked.

Victoria goes to her sister's bathroom, raises a heavy brass candelabra and brings it down on Gail's head again and again, then drags the lifeless body to her own bathroom, and then returns to her easel where she paints furiously.

Calling the house, Cooper is alarmed when Victoria answers the telephone, hurries to the house, has to break in, and discovers Gail's body. He realizes the horror of the situation in which he is right in the middle. He carries Gail's body to his car, places it in the back seat, covers it, returns to the house.

Moments later when Victoria is in his arms, leaning on his shoulder, she glances up at a corner of her room and shrieks. . . .