While searching for missing teenagers, novice skip tracer Maggie McKeown (Heather Menzies) and one of the locals, town boozer Paul Grogan (Bradford Dillman), stumble upon a top-secret Army laboratory doing genetic research on piranha for the purpose of biological warfare. When they are accidentally released from the compound, the deadly school of eating machines head downstream and eat everything and anything in their path. Piranha features a stellar group of talent in front of as well as behind the camera. The top-notch cast of cult stars includes Kevin McCarthy (Invasion of the Body Snatchers), Barbara Steele (Black Sunday), Belinda Balaski (The Howling), Dick Miller (A Bucket of Blood), Paul Bartel (Eating Raoul), and Richard Deacon (The Dick Van Dyke Show).