When irascible boss T.R. Hollister (Jim Backus) threatens to pull the plug on an underwater environmental living project, employee Fred Miller (Tony Randall) and his wife, Vivian (Janet Leigh), take their family down in the deep to live for 30 days. With all the modern conveniences of a home on land, the family even invites a rock & roll band to get down and record. Merv Griffin (himself) arranges an underwater interview for his television show while Mel Cheever (Ken Berry) schemes to get Fred's job back on dry land. Two of the Miller kids, Lorrie (Kay Cole) and Tommy (Gary Tigerman), join three others (Richard Dreyfuss, Roddy McDowall, and Lou Wagner) in the rock band. Friendly dolphins fend of shark attacks as the land sharks try to scuttle the underwater project in this family film. Music is provided by Jeff Barry.