Kitty (Susan Scott) is waiting for her boyfriend Alberto (Robert Hoffmann) when she witnesses a murder through a coin-operated telescope. The woman is slashed to death by a black clad killer who carries a cane and limps. The police don't believe her at first, but later the corpse is discovered in the park. A peanut vendor who works in the area is next to die, followed by a string of brutal murders (a cleaning lady, a dancer, etc.). Alberto at one point becomes a suspect, as he carries a cane and has a limp. Some amateur sleuths decide to solve the murders and focus their attention on a nearby dance academy.