An earthquake spells danger for Sealab when the recurring mass of shock waves ruptures exposed canisters of radioactive waste.

An approaching red tide has more than the fish in a panic - the murky oceanic flux, which initiates a process of oxygen depleting, could cut off the life support system of Sealab.

A red alert is signaled after a supply ship's concrete mooring, cast off during a hurricane, unwittingly strikes Sealab's control dome and splits a major section of the shell.

A new world opens up for Roger Cummings, a crippled boy whose father is doing research at Sealab, when Bobby befriends him and teaches him how to dive.

The entire Sealab complex is threatened by an increasing buildup of aggressive sharks in the area.

When a space probe loses its parachute during reentry and plummets out of sight into the ocean's depths, the staff of Sealab is called on to locate it.