Flipper is abducted by Keith Ricks' old fraternity brother to serve as the chief entertainment at a new Cuban resort hotel. Ricks and Pam Blondell attempt to sneak into the Caribbean country to rescue the dolphin, but are captured and imprisoned by the Cuban Coast Guard.
Flipper refuses to perform for the grand opening of a Cuban hotel resort. With the help of a beautiful local woman, Ricks breaks out of jail and plots to rescue the dolphin before the vengeful resort owner can kill the reluctant dolphin.
Mike and Maya take the Institute's new submersible out to sea to try to photograph the mermaid the two youngsters think they saw. Mike's inexperience places them in deadly peril when they get trapped hundreds of feet below the ocean surface.
Allison Van Rijn, a beautiful underwater photographer with a pet moray eel, moves to Bal Harbor and corpses begin to accumulate immediately thereafter. Keith and Flipper don't trust the newcomer, but Pam stands up for Allison.