Coke-Bottle Glasses (CBG) puts a glass down on Sydney's tray. Realizing that it's a bomb, she throws it to an empty corner, where it explodes. CBG detonates another bomb and, as the crowd panics, he grabs the briefcase and heads toward the exit.
Syd tackles CBG and they exchange blows as the Hydrosek case skids across the floor. He escapes. Dixon shoots a thug about to kill Vaughn as he goes after the briefcase. Kradic gets to the briefcase first and runs.

Dixon and Vaughn follow Kradic into the basement. Cornered, Kradic threatens to drop the Hydrosek in the filtration grate of the city's drinking water. Dixon pretends to lower his gun, then shoots Kradic.

After learning of CBG's failure to steal the Hydrosek, Sophia invites Nadia and Weiss over for dinner. Upon their arrival, Sophia takes Nadia's belongings - which include a laptop - to a back room. CBG emerges from the shadows and hacks into the laptop, gaining access to APO files.

At APO, Syd tells Vaughn that she hasn't seen her father in two days. They go to his apartment and find a notebook with recent records of Jack's vitals. Inside the bathroom, they find containers of medication and blood-soaked bandages in the trash can.

Jack visits Dr. Liddell, who says that years ago during an experiment he discovered that a lethal dose of an alkylating agent cured a few genetically mutated rats --but 84 percent died. Despite Dr. Liddell's warnings, Jack acquires the lethal chemical.

Based on the meds she saw at Jack's place, Syd asks Marshall to research cures for radiation sickness. Marshall reveals that Jack got sick when he removed the fuel rods in a radioactive lab in order to save Sydney. Marshall adds that there is no cure.

Sloane tells the team that Jack needs help and Syd adds no area hospitals have any record of his admittance. She says Jack's mental capabilities might be impaired at the moment and someone might be preying on him, promising a cure.

Jack returns to Liddell's office. Meanwhile, the APO team locates Jack's car in a seedy neighbourhood. Syd and Vaughn drive to the location and arrive at an abandoned building, where they find Jack on a bed in the middle of a big empty room. He injects himself and begins convulsing.

At the APO office, Vaughn explains to Sloane that Jack thought he had a cure, and unfortunately, Jack's condition is irreversible after 72 hours. Vaughn also mentions that Jack has been suffering from hallucinations and woke up briefly to look for a "Dr. Liddell." Sloane tells the team that 25 years ago, Liddell developed a thesis on the treatment of genetic mutations. He went to the Soviet Union in 1981 to spy for the US. When his cover was blown, Jack's extracted him and gave him a new identity. Only Jack knows where Liddell is.

Jack wakes up and talks to Sydney, referring to her as "Laura," Irina's cover name. Sloane suggests using these hallucinations to convince Jack that he's living in '81 -- specifically, the day he extracted Liddell from Russia. He proposes recreating Jack's surroundings to guide his delusions and make him reveal where the actual Liddell is located.

Looking like Irina, Sydney enters a room built to resemble her old house. As the team observes, Jack responds to the scenario. Vaughn calls, pretending to be Jack's handler, and asks what arrangements he needs to make for Liddell. Jack reveals where Liddell should go -- in code.

Believing that Syd is his wife, Jack tells her that he needs to leave town and help Liddell get a new identity in Finland. Jack continues on about his deep regret of missing Sydney's birthday and his lack of involvement in her life. Syd listens, deeply touched.

Marshall asks Nadia why she requested that the Hydrosek be moved. Realizing that someone has hacked into the system, Nadia and Weiss go to the facility where the Hydrosek is stored and find that it's been stolen. CBG lies dead in front of the vault.

Syd finds Dr. Liddell in Helsinki. He accompanies her back to APO and sees Jack, who asks if he's cured yet. Liddell answers, "Not yet… but I'm going to make you better."