Leo Kroll is a doll collector and a mother-fixated lab technician. In addition, he is a serial murderer who has killed several nurses. The authorities ask him about these killings, but he is freed. Clara, the nurse who has been caring for his possessive mother, who is in the hospital following a heart attack, is Kroll's next victim. He does, however, leave a toy at the crime scene. (In a side story, Kroll falls in love with Tally, one of the girls who works at the amusement park booth where he gets this doll.) Police question Kroll once more before releasing him when he passes a lie detector exam. After telling his mother how he killed Clara during a hospital visit, he has a second, deadly heart attack. When he returns to the amusement park, he witnesses Tally's coworker Barbara speaking with the police. Kroll is furious about this. Kroll is clearly anxious as he discusses the police with Barbara. As he plays the game, he misses ring after ring. Kroll is ultimately triggered when Barbara says "Mama" in imitation of one of the dolls, reminding him of his mother. As Barbara exits the shower at her apartment, Kroll approaches her and strangles her. The cops are confused when a girl who works at an amusement park booth rather than a nursing home is killed. Kroll appears to be at last free now that his mother is deceased, and his distaste for women appears to be lessening. He goes to see Tally and pops the question. Kroll starts to think that what his mother warned him about women is true after he is rejected. The cops eventually locate their strangler after questioning Tally and obtaining a description. Kroll waits to murder Tally when she gets home while hiding in her apartment. The police bug Tally's room and remain nearby in an attempt to get Kroll since they think she might be the strangler's next victim. Tally ends up hiding the bug in her room while she packs to leave town. When Kroll emerges and starts strangling Tally, the police cannot hear what is happening. The officers stormed into the room and started shooting. It is unknown if Tally has lived; Kroll is struck, falls through the glass, and dies.