Debbie wants to have a baby so she starts to interview the crew to see who will be the father. Marco makes time with the other Debbie (aka "Black" Debbie).

An accident leaves Quinn comatose and Stormy allegedly smarter. Have they really switched brains?

A loophole in the Sealab charter turns everyone into captains, except Stormy (too stupid), Quinn (too proud to exploit the loophole), and the Chinese crew members (because of previous Asian accomplishments, including anime, among other things). How will Sealab survive? And where did Capt. Murphy go?

Debbie and Quinn break up, while Dr. Virjay gets his old rock band back together.

Captain Murphy opens Sealab to tourists, eventually prompting Dr. Virjay to renounce his religion, and begin to eat meat from cows.

Kommissar Murphy brings Marxist-Leninist ideals to Sealab.

As Captain Murphy leaves for The Great Spice Wars, a new captain, Tornado Shanks, is given the helm.

The cast looks back over five years of "A Legacy of Laughter" in the style of one of those tacky TV reunion specials but of course since this IS Sealab, not all goes well.