Bud plays catch with flipper, teaching him how to retrieve items from the ocean floor. An SOS comes through; Bill Darmon has been attacked by a shark and needs blood urgently. Porter contacts the Coast Guard to arrange the blood delivery before going out with Bud to rescue Bill. The helicopter arrives but during the transfer the blood is lost overboard. A number of attempts are made to retrieve it but a persistent shark stops all efforts till Flipper comes to the rescue, fights off the shark and brings the blood up.
After Bud sees a car at the bottom of the bay with bullet holes int he windshield, he asks his father to investigate. But Porter is used to Bud's exaggerated stories and vivid imagination and declares he doesn't have time. Before leaving for a meeting, he orders his sons to stay away from the car, but the boys soon find a pretext on which to once again go to that section of the bay. Unfortunately, they had already questioned several people about the car and one of them is responsible for that car. The boy soon learn a lesson in why it's very important to obey your ...
Mike Belden gets to spend some time with the Ricks family, after his mother remarries and heads out for a honeymoon. As a city boy he struggles to adapt to the lifestyle of the Florida Keys. He is concerned about his mother remarrying and seems on a path of self destruction, first crashing a speedboat then disobeying diving instructions. Ultimately he talks Sandy into diving a dangerous wreck, where they become trapped and only the quick thinking flipper alerts Sandy's father and the boys are saved just as their air runs out
An old man fills Bud's head with heroic tales, but his father warns him all the stories aren't necessarily true. Circumstances force Bud to realize then, but he wants to be a hero by finding the poachers who almost killed his father.
When Po sends the boys on an important errand, he tells the boys to leave Flipper at home. Flipper's life is in danger after it's believed he ate a rare fish that had been studied for many years. Bud and Sandy must get to their dad and warn him within a half hour. But they soon discover the truth and wonder how they'd get themselves out of their mess.
When a cranky man chases the boys from his boat, they decide he's up to no good. But when they return they meet a couple of thieves who really ARE up to no good. Their trusting the wrong people could get them killed.