A spacecraft, presumed to be of alien origin, is discovered on the floor of the Pacific Ocean, estimated to have been there for nearly 300 years. A team of experts, including marine biologist Dr. Beth Halperin (Stone), mathematician Dr. Harry Adams (Jackson), astrophysicist Dr. Ted Fielding (Schreiber), psychologist Dr. Norman Goodman (Hoffman), and U.S. Navy Capt. Harold Barnes (Coyote), are assembled and taken to the Habitat, a state-of-the-art underwater living environment located near the spacecraft.