| Director | Francis D. Lyon |
|---|
US Navy Commander Wayne has arrived at Topside, the support vessel for the civilian Institute of Marine Sciences' Sealab, a facility on the ocean floor. He is there because an unidentified object has been spotted circling Sealab. Cmdr. Wayne rides a diving bell down to Sealab, where he meets its director, Dr. LaSaltier and marine biologist Dr. Rene Peron. During Cmdr.