As he and Julian Bashir wait in line for lunch, Garak appears to be having severe headaches. He refuses to allow Bashir to help, becoming irritable and leaving to Bashir's bemusement. Confiding in Jadzia Dax, Bashir realizes he hardly knows the man with whom he has been eating lunch for over almost two years. He later hears Garak discussing a deal of some sort with Quark and becomes suspicious. The next day, Quark calls the Infirmary and asks Bashir to come to the bar immediately. There he finds a heavily intoxicated Garak who, after a brief struggle, collapses in pain.
Bashir finds that Garak has an implant of some sort in his brain, which he believes is related to whatever Garak and Quark were discussing the night before. He solicits Odo's help and the two of them eavesdrop on Quark later that night. Quark tries to order a piece of Cardassian biotechnology, which turns out to be classified by the Obsidian Order. Constable Odo explains that the Obsidian Order is "the ever-vigilant eyes and ears of the Cardassian Empire," an intelligence service more ruthless than the Romulan Tal Shiar. When Bashir returns to the Infirmary, Garak is gone.
When he arrives at Garak's quarters, Bashir finds the Cardassian has taken massive doses of a tranquilizer, enough that any normal person would have passed out. Garak is obstinate but eventually reveals that the implant was given to him by the head of the Obsidian Order, Enabran Tain. It was designed to make him resistant to interrogations if caught, but he has been using the implant to cope with the pain of living in exile. However, it was never designed for continuous use and is breaking down. Garak claims he deserves his punishment and tells how he once destroyed a ship containing 98 Cardassians, including his best friend, Elim. He then collapses.
Bashir turns the implant off and, robbed of the endorphins it produced, Garak becomes extremely agitated. He explains that Elim was his aide, and rather than killing Elim, he was exiled for releasing a group of Bajoran children he was supposed to interrogate. The worst part of his exile, he says, is that he has actually begun to enjoy life aboard Deep Space Nine, which he calls "torture". After expressing disdain for the station and Bashir, Garak again loses consciousness.
Medical tests reveal that, even with the implant off, Garak is still dying. Bashir is unable to explain why and considers turning the implant back on. However, Garak refuses to ever activate it again and decides to tell Bashir the "truth," which Bashir has given up on finding. In the new version of events, Elim was not Garak's aide but his childhood friend. The two were both powerful men in the Obsidian Order until a scandal erupted involving someone who released a group of Bajoran prisoners. Panicking, Garak tried to frame Elim, but he beat Garak to the punch and Garak was exiled. Bashir then decides that the only way to save Garak is to find Enabran Tain, the man who put the implant in Garak's head.
Bashir finds Tain, who reveals that he has been monitoring Garak. He tells the doctor that if he were truly Garak's friend he would allow Garak to die; however, he agrees to give Bashir the information needed to counteract the effects of the implant. Before departing, Bashir asks Tain what truly became of Elim. Tain simply laughs, confusing Bashir. Elim, Tain says, is Garak's first name.
Garak makes a full recovery and resumes his weekly lunches with Bashir. During his recovery, he heard a strange rumor: Odo thinks Garak was once a member of the Obsidian Order. Pressed for "real answers," Garak tells the doctor that he has given all the answers he is capable of, and that they are all true - especially the lies.