Bridger responds to a plea from an old girlfriend living in an underwater colony that has been dedicated to non-violence.

After ten years of peace, the citizens are trying to kill each other.

Ford discovers an ancient warrior's helmet and sword that prove that the lost continent of Atlantis did exist.

The helmet though may carry a deadly curse that could destroy Bridger and the crew.

Lucas oversees the maiden journey of a revolutionary new underwater train, while Ford and Henderson go on a secret date as passengers.