Following the Gill-man's escape from Ocean Harbor Oceanarium in Florida, a team of scientists led by the deranged and cold-hearted Dr. William Barton (Jeff Morrow) board the ''Vagabondia III'' to capture the creature in the Everglades. Barton is mentally unstable and apparently an abusive husband to his wife Marcia (Leigh Snowden), as he becomes very jealous and paranoid when Marcia is with other men. Their guide Jed Grant (Gregg Palmer) makes numerous passes on Marcia (which she constantly rebuffs), with Barton becoming paranoia about the two.