When Captain Hunter and the crew of the Endeavor come across an alien ship, they have no idea what caused the deaths of its entire crew. Could they be infected with some unknown virus? Or did they simply all go mad and kill each other? Once Dr. Klein rules out infection, it seems like they're in the clear. Until, that is, some strange phenomenon invades the ship. Suddenly, crew members are acting strangely and the ship's course keeps changing against orders. To make matters worse, Commander Bishop and Captain Hunter port down to the aliens' home world to investigate, and end up imprisoned. Now, it's up to the rest of the crew to free them and save the ship...and themselves.