The ''Defiant'' makes a supply run to planet AR-558, the site of a Dominion communications relay that Starfleet captured. The relay has been under constant siege, with the crew defending it overdue to be relieved by a new crew. Sisko, Bashir, Nog, and Quark find themselves stuck on the planet and having to help hold the relay against a Jem'hadar batallion, while dealing with deadly Dominion booby-traps.

!This episode contains examples of:

* BattleTrophy: Reese keeps a necklace of Ketracel-White tubes hung around his neck.
* BreakTheCutie: Nog gets shot, and his leg is amputated.
* DarkerAndEdgier: One of the darkest episodes of the whole franchise, providing a wholesale {{Deconstruction}} of Roddenberry's vision of an ideal future humanity.
* HumansAreWarriors : At least when you take away their sonic showers.
* ImADoctorNotAPlaceholder: An engineer, not a magician
* NotSoDifferent: Quark spends a lot of the episode moralizing, but in the end he drops the superior attitude, picks up a phaser, and proves that when push comes to shove he can be just as ruthless as any [[FantasticSlur hew-mon]].
* PapaWolf: Quark was quick to defend his injured nephew in the quickest and most efficient way possible: By shooting the enemy that was about to attack them.
* ParanoiaFuel: The invisible floating mines are a disturbing InUniverse example.
* ShellShockedVeteran: Everyone at AR-558.
* ShoutOut: The battle plays out much like the film ''{{Film/Zulu}}''. There's even a scene where Jem'Hadar are expended merely to test the defenses of the camp (of course, these Jem'Hadar were holograms).
* SoldiersAtTheRear: Both engineers, Nog and the poor guy assigned to keep [=AR558=] running.
* SoundtrackDissonance: During the battle
* WarIsHell: This episode shows no glory, no love of battle. Just the harshness and a piece of rock which no one would care about if not for the technology put there.