When an inventor (Tony Randall) needs human guinea pigs to test his experimental undersea dream home, h e packs up his wife (Janet Leigh), his kids and their rock and roll band (featuring Richard Dreyfuss) and takes the plunge. While this average-if extended-family adapts to life on the ocean floor, the band must find a way to get it's groovy new single into the hands of a top record producer before it's too late. Our aquanauts are in for even more deep trouble when greedy prospectors, hungry sharks, a hurricane and a battle-ready U.S. Navy threaten to turn their happy underwater home into a real bummer!