Leo Kroll, a lab technician in a large unnamed city, is responsible for the strangulation murders of several young nurses. He feels that in some twisted way, that he is getting back at his overbearing shrew of a mother. Leo also kills the nurse who is taking care of his mother in the rest home she is staying at. As a result, Mrs. Kroll dies from a heart attack. He also kills an arcade worker whom he feels can identify him.