Lieutenant Dax, preparing to return to her quarters for the evening, is being observed by a male Trill named Selin Peers. Ilon Tandro, a humanoid from Klaestron IV, joins him in the shadows. Confirming Dax's identity with Peers, Tandro and two of his officers succeed in taking her hostage. Bashir, unable to save her, alerts the other officers. Sisko, Kira, and Odo attempt to locate them, but Dax's combadge was removed and left behind. To Odo's amazement, Tandro and the two officers, with Dax in tow, avoid the security tracking grid with ease. To complicate matters, Sisko realizes that the abductors have disabled the station's tractor beam. Kira finally discovers them in an airlock and imprisons the group in a force field. However, they deactivate it and board a Klaestron ship. Sisko, though, manages to get the tractor beam working again, and they are able to keep the ship from escaping.
Forced to re-enter the space station, Tandro informs Sisko that this is an extradition mission. Dax is under arrest — charged with treason and the murder of Tandro's father, General Ardelon Tandro, 30 years ago. Sisko realizes that he is accusing Curzon Dax, not Jadzia, of committing the crimes on Klaestron IV. For some reason, however, Dax refuses to tell Sisko what happened back then.
In Dax's defense, Sisko and Kira tell Tandro that, since the space station is technically Bajoran, an extradition hearing must be held before they can release Dax to him. Quark reluctantly agrees to allow the hearing to be held in his bar. At the hearing, Sisko tries to convince Judge Els Renora that Jadzia Dax is an entirely different entity than Curzon. Due to the unusual circumstances, Renora agrees to extend the proceedings.
Sisko, determined to keep Dax alive, directs Kira, Bashir, and Odo to dig up all of the evidence they can find to prove Dax's innocence. Odo, on Klaestron IV, contacts Enina, Tandro's mother, who claims that Curzon Dax had nothing to do with the death of her husband. She also claims that Tandro is obsessed with his father's death, and that Tandro believes Curzon was responsible because he can establish the whereabouts of all suspects except himself. In short, Dax has no alibi.
The hearing resumes, and Tandro calls Selin Peers, the Trill who helped locate Dax, to the witness stand. Although Peers confirms that if a Trill committed a crime, the symbiont's future host body would know and feel everything involved with that crime, Sisko establishes that with each new host, a new and different personality results from the joining. A recess is called, and Dax remains tight-lipped. She asks Sisko to please end his efforts on her behalf, which leaves him wondering.
Bashir is called to testify that Curzon and Jadzia are two physically distinct individuals. Unfortunately, Tandro then indicates it is impossible to determine whether or not the brainwave patterns of the symbiont have changed since they joined the new host, Jadzia.
In a last effort, Sisko calls himself to the witness stand and allows Kira to interrogate him. She and Tandro take their turns questioning Sisko, after which a one hour recess is declared. Suddenly, Sisko receives an urgent message from Odo on Klaestron IV, that reports all evidence points to Curzon Dax and Enina Tandro having an affair 30 years ago — which grants Curzon a perfect motive for murder. Jadzia, confronted with this information, admits shame over the marital indiscretions, but still neither admits or denies any knowledge of the murder.
Returning from the recess, Dax takes the witness stand. Tandro proceeds to pin her down with questions, when he is interrupted by the surprise appearance of his mother, Enina. She admits, to everyone's astonishment, that Curzon could not have been responsible for her husband's murder. When the crucial transmission was made that resulted in his death, she and Curzon were in bed together. Dax is free to go, Sisko and the other officers are relieved, and life on Deep Space Nine returns to normal.