Marine biologists Jake (George C. Scott) and Maggie Terrell (Trish Van Devere) have for many years been doing dolphin research in the Florida Keys, and have even coached some dolphins to speak primitive English. But when two of the dolphins are kidnapped, an investigation proves that the Terrells' financial backers, the Franklin Foundation, have had sinister intentions all along. The dolphins are to be used to deliver and detonate explosives beneath the president's yacht.