During a savage typhoon, the crew of a salvage tug discover a seemingly deserted Russian military vessel. Everton (Donald Sutherland), the tug's captain, & Kit (Jamie Lee Curtis), his navigator, manage to restore the power, only to discover a surviving scientist who begs them to turn the power off & abandon the ship. It then emerges that the ship has been taken over by a hostile & elusive alien lifeform determined to destroy the 'virus' that is mankind.