When Temporal Investigations arrives on DS9, Sisko recounts how he and the crew of the Defiant traveled back in time to prevent the assassination of Captain James T. Kirk during the original Enterprise's mission to Space Station K-7.

Sisko, Dax, Odo, and Garak find themselves trapped seven years in the past on Terok Nor, but everyone thinks that they're condemned Bajorans. With Cardassians in control of the station, Odo's memory of a crime he once investigated may be the only key to their survival.