As the seaQuest undergoes inspection, Lieutenant Benjamin Krieg has a close encounter with an unknown life form while in a seaCrab in the Tonga Trench.

When the creature lets him go, Krieg discovers a treasure trove of mysterious glowing stones; stones that may mean big money.

However, is the bigger threat to seaQuest the greed that overtakes the crew or the unknown life form?

When the air conditioning breaks down in the crew quarters, Krieg has no choice but to turn to "The Regulator".

He's a cut-throat black market trader who hides a shamed past with whom Bridger is familiar with and whom Lucas finds he can sympathize with.

The first manned mission to Mars returns home to Earth, led by Commander Scott Keller, an old friend of Bridger's.

However, a malfunction during re-entry plunges the capsule into the ocean where a corrupt general from a foreign confederation races to recover the astronauts before the seaQuest can.

In preparation for an experiment, the crew evacuates the seaQuest, leaving only Commander Ford, Lt. Commander Hitchcock, Lieutenant Krieg, Chief Crocker, and Lucas aboard.

However, environmental extremists use the seaQuest's vulnerable state to seize control of the boat.

UEO Secretary General Andrea Dre travels aboard the seaQuest en route to a conference where she invites Lucas to join her to speak out on his work with Darwin.

However, Lucas soon finds himself held hostage along with the leaders of the other UEO confederations.

When Commander Ford believes he saw a mermaid at the bottom of the ocean, Captain Bridger orders him to take shore leave.

While on leave, Ford encounters the same woman again and soon finds himself ensnared in a mysterious scientist's unnatural experiment.

Meanwhile, Lucas sneaks away to a party where Julianna and he may go “all the way.”

Piccolo's estranged father seeks his help after his wife becomes addicted to an experimental drug.

When Bridger and Smith are discovered in an embrace, rumours spread like wildfire about their supposed shipboard romance.