For no apparent reason, famous psychoanalytical scientist Andy Shaw is attacked and badly beaten by a group of well-dressed youths while he is walking alone down a deserted road. When the police, including investigating juvenile officer Detective Smith, are in his opinion too slow and too busy finding the criminals, Shaw decides to go after them himself.
Andy proves to be an amateur sleuth at best, going over ground already covered by the police. His wife uncomfortably watches him buy a gun and take target practice on a tin can. One night, Andy sees a convertible that resembles his attackers, and gives chase at high speed. The driver is a frightened teenage girl who calls the police, and Andy spends an uncomfortable night in the holding tank before Smithy releases him.
Shaw hires Albert Anastasia, a private investigator, whose assignment leads him to Chuck Lang, the leader of the gang. Andy's relentless quest for revenge leads to a gang member committing suicide. Lang counters by taking Anastasia to a dangerous stretch of road where he is killed, then comes to Andy's house where he threatens his wife, then plans to shoot Andy when he returns home. Lang escapes from the police but as soon as Andy learns of him, he goes straight to the boy's house and beats him up badly. On the verge of killing him by drowning him in his family's swimming pool, Andy finally relents, handing Lang over to Smith to arrest him.