Richard O'Barry

As Coral Key Park prepares for its annual swimming race, Porter Ricks falls victim to toxic chemicals during an underwater investigation. With Porter hospitalized, Sandy unknowingly prepares to lead young swimmers through dangerous waters.

A young diver's decision to leave his teaching position for dangerous coral blasting work leads to disaster. As Porter and Sandy race to prevent tragedy, Flipper battles underwater with the nitrogen-affected diver, trying to save him.