The Federation starship Defiant carries the senior staff of Deep Space Nine into the Gamma Quadrant to settle trade arrangements with the Karemma representative, Hanok. As the Dominion disapproves of trading with the Alpha Quadrant, the talks take place secretly in orbit around a gas giant. The Karemma are upset over the expense of doing business with the Alpha Quadrant, especially regarding all the tariffs that the Federation's trade representative, Quark, said must be imposed. They are further angered when the now upset Captain Sisko informs them that they've been cheated: the "tariffs" were means Quark used to line his pockets with extra profit.
The negotiations are interrupted when a pair of Jem'Hadar ships burst in and fire on the Karemma ship. The Jem'Hadar chase the ship into the atmosphere of the gas giant, and the Defiant takes off in pursuit. The Jem'Hadar open fire on the Defiant, crippling it in the turbulent fluorine atmosphere of the planet.
Science Officer Jadzia Dax heads below to try to help patch up the engines so the ship can escape the planet's atmosphere. She is successful but is nearly blown out of the ship when the hull is breached. To save the rest of the ship, Dr. Bashir is forced to seal off the breached area with Dax still inside, but he seals himself in the breached section so he can help her. They remain trapped in a turbolift with a diminishing supply of oxygen and without communication with the bridge, where the rest of the crew presume them lost.
As the engines come back on line, one of the Jem'Hadar ships attacks. The Defiant destroys it, but not before it is able to render the Defiant helpless again. The ship is dark and smoldering, running on emergency power, and Captain Sisko has been gravely injured with a concussion. Major Kira tends to him, trying to keep him conscious.
Meanwhile, Quark is trapped in the mess hall with Hanok the Karemma, where they find themselves staring at the nose of a live Jem'Hadar torpedo which has lodged itself in the hull. Quark and Hanok are wary of each other at first, but then realize they can combine their cleverness to come up with a plan to defuse the torpedo. Dax and Bashir huddle together for warmth, as they have only a thin bulkhead separating them from the frigid vacuum of space - Bashir appreciates the irony that being trapped in a turbolift with Jadzia in his arms was once a fantasy of his. On the bridge, Kira cares for Sisko, telling him a Bajoran fairy tale to try to keep him awake. Lt. Cdr. Worf and Chief O'Brien work on putting the Defiant's engines back together. After playing a game of cat and mouse, the Defiant is able to destroy the second Jem'Hadar fighter and rescue the Karemma crew.