
The Enterprise investigates the disappearance of its fellow starship the U.S.S. Defiant . Kirk takes a team over and they find the entire crew dead, having killed each other in fits of madness. The Defiant starts to vanish and everyone but Kirk makes it back before it disappears for good. Spock orders the Enterprise to stay in the area to attempt a recovery, but the crystalline Tholians launch an attack and the Enterprise crew start to experience the same madness that destroyed the Defiant crew.
