Hoodlums and law abiding citizens alike are endangered when a Fagan-like character uses a mentally deranged teenager to inflict revenge in "Vendetta." The downtown section of town is being terrorized by Arty Riis, a scruffy character who specializes in coercion. With a scary Pied Piper skill, Arty surrounds himself with juvenile delinquent followers - his favorite being a teenage escapee from an institution for the criminally insane. Arty's young strong arm "protects" him from "double-crossers" with violent tactics, smashing one thug's kneecaps with a lead pipe, and in a fit of jealousy, murdering another of Arty's juvenile followers. When Starsky and Hutch cross Arty's path, they both get a sample of Arty's vengeance. Starsky's tires are slashed. Hutch gets a brick through his window, a dead rat in his refrigerator, a bomb in his car radio and, ultimately, his girlfriend is visited by the mentally deranged "hit kid."