New York City is in a panic caused by an insane murderer; Maria, a police officer is entrusted with the case; to do this, she pretends to be a prostitute. One night, she meets a possible suspect who holds her and her partner hostage.

People are dying mysteriously and gruesomely, and nobody has a clue what the cause is. Only health worker Mike Brady has a possible solution, but his theory of killer slugs is laughed at by the authorities. Only when the body count begins to rise and a slug expert from England begins snooping around does it begin to look like Mike had the right idea after all.