A runabout is shrunk by a space anomaly, and its tiny crew must slip inside the Jem'Hadar-captured Defiant to help retake it.
While the Defiant studies a subspace anomaly, Dax, O'Brien and Bashir fly the runabout Rubicon into it and are shrunk to a few centimetres. A Jem'Hadar ship then disables and boards the Defiant, whose commander, Kudak'Etan, is contemptuous of his more experienced Gamma Quadrant-born second, Ixtana'Rax, and forces Sisko to repair the warp drive.
The miniature runabout re-enters the Defiant through a plasma vent, and its crew helps Sisko's people regain control, with O'Brien and Bashir beaming into a computer node to restore the command codes. Sisko exploits the rivalry between the two Jem'Hadar officers, and his crew retakes the ship.