While Nelson and Sharkey search by air for an uncharted island, Seaview brings aboard a gigantic egg from the bottom of the sea during a routine specimen collection. It later hatches a fully grown, orange creature which kills a background guy and tosses Kowalski around the missle room. Nelson returns and (in a very un-urgent manner) has the crew hunt down this grunting thing as it terrorizes the crew. Later, Crane and Kowalski take the flying sub out to investigate the area, crash landing near the uncharted island. Another orange crature (one that speaks and is the leader) captures them and brings them to creature HQ. The monsters are aliens from Scorpious which are trying to hatch millions of eggs. Can the crew stop this invasion before these amphibian aliens take of the Earth?
Elenco: Richard Basehart , David Hedison , Robert Duvall , Terry Becker , Del Monroe , Paul Trinka , Richard Bull , Robert Dowdell .