A telepathic echo sets the crew on a path to mutiny.
A dying Klingon arrives from a ship destroyed in the Gamma Quadrant, and soon the senior staff start acting strangely. Kira plots against Sisko, O'Brien sides with his commander and Sisko becomes absorbed in building a clock, while the tension between them keeps rising.
Odo, who is not affected, finds that a telepathic record from an alien world has imprinted the crew with the roles in a power struggle that destroyed its makers. Odo pretends to side with both camps, gets Bashir to devise a way to drive out the influence, then lures everyone into a cargo bay where the energy is drawn out and vented into space.