On the run from the Jem'Hadar, Amaralan ships have passed through the wormhole into the Alpha Quadrant. Unfortunately, they've brought they Jem'Hadar with them. The subsequent battle damages DS9 and forces the whole thing through the wormhole.
When Sisko, Worf and Bashir return to Bajor after a trip elsewhere in Federation space, they are more than shocked to discover that Kira, Oda and the whole of DS9 simply . . . isn't where it's supposed to be. The Captain must now find a way to return DS9 to its proper location before the Bajoran government withdraws from its treaty with the Federation, the Amaralans start to suspect that DS9 is a secret weapon designed to conquer their homeworld, and the Jem'Hadar attack the defenseless station on the other side.