Detroit Detective John Valentino knows El Camino Drive all too well. His father was murdered there on Halloween, 1978. Antonio Valentino was killed after work by three men, alleging he was having an affair with one of their wives. Claiming self-defense, the murderers are exonerated, believing that a toy pistol in the victim's pocket was an actual weapon. After the murder trial, a family vendetta is loudly placed against his father's killers.
Forty years later, Detective Valentino is now an alcoholic, losing his wife and family to his drinking. After his mother dies, he cleans out the attic of her home, to find a wooden truck with an evidence bag from the night of the murder. Included, is a blood-stained, water pistol he once owned as a little boy...the very toy pistol his father used to fool his killers.
One evening, the wife of one of the murderers is found brutally stabbed in her ex-husband's mobile home. Next to her body, is the stanza of a poem and a toy water pistol. Valentino, the prime suspect, has no idea who the "Water Pistol Killer" is.
With every new murder, there's a new stanza to the poem and a toy water pistol, lying next to the body....