James Cameron got his start electroshocking worms on low-budget Corman movies, and with Piranha II gets his first chance to direct on a Corman movie sequel project that was bought up by Italians.

A scuba diving instructor, her biochemist boyfriend, and her police chief ex-husband try to link a series of bizarre deaths to a mutant strain of piranha fish whose lair is a sunken freighter ship off a Caribbean island resort.