While investigating a black smoker, Darwin becomes seriously ill.

Bridger must contemplate setting his long-time aquatic pal free in order to save his life.

The seaQuest discovers the lost Library of Alexandria sunken beneath the sea.

However, when surrounding nations cannot agree on a peaceful way to share the discovery, Bridger must act as mediator before escalating tensions result in the destruction of the library.

When Bridger is hurled across his quarters by an unknown force, it leads the seaQuest to find a hundred-year-old sunken ship.

The spirits of those who perished there haunt its ancient hull, one of which possesses Dr. Westphalen.

Commander Ford, Dr. Westphalen, Lucas and Lieutenant Krieg are trapped on the surface of the ocean as a hurricane rages above them.

Meanwhile, suffering severe damage from a lightning strike, the seaQuest must desperately search for a sunken French submarine before its passengers, all children, run out of air.

Dr. Raleigh Young's magma buoy launched from the seaQuest months earlier rockets out of the sea and crash lands onto an island.

A group of treasure hunters believe that the UEO is on their way to steal the fortune they hope to find.

When an environmental radical begins to sink whaling ships, the UEO orders Bridger to find the attacker and destroy him.

However, Bridger refuses on moral grounds and resigns as captain of the seaQuest.

While visiting Dr. Westphalen is visiting Malcolm Lansdowne, the two of them are captured by ousted dictator and escaped UEO prisoner Milos Tezlov, who wants Malcolm's dolphins to train for militaristic purposes.

However, when Kristin notices Tezlov's autistic son Caesar taking an extreme liking to dolphins, she forges a deal for her release, granting Tezlov passage aboard the seaQuest.

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.”

The seaQuest makes the biggest discovery in Human history when they discover an alien starship entombed in an undersea rock face; trapped there for over a million years.

When an away team goes inside the ship, they find that they might not be the only thing aboard it.

When genetically engineered people, no longer happy with their captivity, stage a revolt, seaQuest, with some new faces are called in to help.

When genetically engineered people, no longer happy with their captivity, stage a revolt, seaQuest, with some new faces are called in to help.