Dr. Bashir is excited to meet Garak, the last Cardassian aboard Deep Space Nine and a rumored spy. He rushes to tell the rest of the crew, but they are busy rescuing a Bajoran, Tahna Los, whose ship has been attacked by Cardassians. Tahna and Kira instantly recognize each other from their days in the Bajoran underground. The Cardassians hail Sisko and demand he turn Tahna over to them, saying he is a member of a Bajoran terrorist group called the Khon-Ma. However, Tahna renounces terrorism and asks for asylum, and thanks to Kira's impassioned plea to a wary Sisko, he gets it.
A day or so later, Klingon sisters Lursa and B'Etor arrive at the station and arouse Odo's suspicions, prompting him to tail them to a secret meeting with Tahna in the Cargo Bay. Odo assumes the shape of a rat and follows them in, and overhears as they demand a payment in gold from Tahna in exchange for an undisclosed item.
Sisko gives Kira approval to help two more Khon-Ma members receive asylum. But when Odo informs him of the exchange he witnessed in the Cargo Bay, Sisko is suddenly unsure of Kira's loyalty. Meanwhile, Lursa and B'Etor visit Garak in his shop, where they make a deal to trade Tahna for more gold. And in Tahna's quarters, Kira is shocked when he reveals that he is still a member of the Khon-Ma and came to Deep Space Nine on purpose, to enlist her help in a plan to win Bajor's freedom.
On the Promenade, Garak seeks out Bashir and asks the doctor to meet him in his shop at a specific time. Confused, Bashir runs to Sisko, who suggests he attend the meeting. When he arrives at the shop, Bashir is hustled into a dressing room just before Lursa and B'Etor arrive. Hidden from view, he overhears as Garak gets them to reveal that they are selling Tahna a cylinder of bilitrium, an ingredient needed for a very powerful bomb.
The entire crew assembles to discuss the dangerous situation, and after much deliberation, Sisko decides to let Kira take Tahna to meet the Klingon sisters. The exchange is made, and Cardassian forces, alerted by Garak, appear and threaten to fire. Sisko and O'Brien threaten to fire as well, but all are forced to let Tahna proceed with his plan when he reveals that his bomb will spread radiation across the entire system. He tells Kira that his target is the wormhole, which he wants to close off in order to diminish Bajor's importance to the Federation and the Cardassians so that they will leave the planet to the Bajorans. He attempts to release the bomb, but Kira is able to delay him so that the bomb explodes harmlessly at the other side of the wormhole. The pair are then transported back to the station, where Tahna is arrested and Kira is left to wonder whether she betrayed or helped her people.