A virus found on board a sunken space station infects the crew.

As Bridger rushes to find the inventor of the pathogen, a warrior submarine from an opposing confederation arrives to cover up their crimes, even if it means the destruction of the seaQuest.

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.