An ambulance brings a heavily-bandaged patient in to a New York City hospital. In nearby Room 103, Napoleon is checking on his hospitalized partner Illya. He insists that Illya needs bedrest after the concussion he received on a recent mission after jumping off of a train. A nurse comes in and tells Napoleon that visiting hours are over.
The two doctors with the incoming patient take him into an elevator. Once they're inside, the "patient" gets up and the "doctor" with him removes his bandages.
Napoleon says that he has to go, and says that he's going to have a date with the bikini model that Illya rescued. He and the nurse leave, and the two fakes come in. The fake patient, wearing steel-rimmed glasses, is now dressed as a doctor, and they bring a gurney in with them. The imposter introduces himself as Dr. Heller and says that they're taking him out for a consultation on his concussion. Illya points out that the nurse gave him sleeping pills, and he attacks them. They quickly subdue him, inject him with a sedative, and take him out on the gurney. The doctor, "steel Rims," tells his partner "White Coat" to be careful with Illya because he still has ten hours to live.
The two men take Illya to an abandoned building in a demolition zone and wake him up. He finds himself in a gas chamber, and a man with a pet leopard, Ving, is waiting outside. The man, Viktor Karmak, tells his assistant to set the digital timer on the gas chamber and confirms that the message has been delivered. Viktor tells his assistant, Stefan, to pay the two men in full and refuses to pay them any more for the risk they undertook. The men ask about their escape plan, and Viktor says that Stefan will make the arrangements for their final disappearance.
Stefan leads the two men up the stairs... and they fall through a trap door. Once Stefan has eliminated them, with two well-placed gunshots, Viktor walks over to the chamber and looks in at Illya, who recognizes him.
At U.N.C.L.E. HQ, Waverly tells Napoleon that Viktor has grabbed Illya. Napoleon points out that Viktor died two years ago when his own people staked him out for scavenger ants. The two agents buried what there were of Viktor's remains. However, Viktor resurfaced in Brazil two months ago, and his visa paperwork confirms that it's him. Waverly warns that Viktor wants Napoleon to find him since Napoleon and Illya were responsible for his downfall. Viktor sent a cockatoo trained to say that Napoleon has to rescue Illya by twelve o'clock or Illya will die. They have 52 minutes left, and Napoleon and Waverly figure that the number 12 is significant. Agents have checked all of the obvious locations.
Waverly orders his agents to flood the area, and Napoleon warns that Viktor may spot them and kill Illya immediately. He refuses to let Napoleon go in alone unless Napoleon has an alternate plan, and Napoleon admits that he doesn't. Once Waverly leaves, Napoleon checks the maps of the cities and spots a condemned area with the 12 O'Clock Club in the center.
Napoleon goes to the abandoned club, and Viktor watches him go in. Inside, Napoleon finds a modern artist, Sheila Van Tilson, working on her art. She assumes that he's with the health department and refuses to move. Napoleon asks why she's there, and Sheila admits that she's a starving necklace despite the expensive necklace that she's wearing. When Napoleon points it out, Sheila says that her father gave it to her. He doesn't believe her, and knocks over one of her sculptures. Sheila complains and Napoleon figures that she's legitimate, and says that she's leaving out immediately.
As Napoleon drags her out, Viktor addresses him from the shadows and congratulates him on passing the first test. He tells Napoleon to stay where he is or he'll kill him immediately, threatening to unleash his leopard. When Sheila tries to leave, Viktor fires a warning shot and figures that she will even up the odds of the hunt. He says that he plans to stalk him with Illya as the bait. Stefan steps out of the shadows and Viktor orders Napoleon to hand over his weapons. Once he does, Viktor tells him that if he dies then Illya will as well. At midnight, Viktor says that the hunt will begin before disappearing back into the shadows.
A Mallet, A Chisel and Thou...
Napoleon and Sheila go back into Sheila's studio, and Napoleon says that he'll have to play along with Viktor in hopes that he makes a mistake. He finds a chisel and hammer, and she explains that her father owns the entire area. Her father was going to give her a studio, but she refused so that she could suffer as an artist.
In the chamber, Illya is strapped to a chair. Despite that, he manages to break the glass his captors have given him and starts cutting through the straps. Stefan comes in to remove the food and notices the glass is missing. He realizes that the glass is missing and finds the broken shard in Illya's hand. As Stefan takes it away, Illya warns that Viktor won't let Stefan survive. Stefan insists that his employer is loyal, but Illya assures him that U.N.C.L.E. will reward anyone who helps him. Viktor calls Stefan out, and Illya tells Stefan to consider his option.
Napoleon leads Sheila out and a nearby payphone rings. The agent goes to answer it, hoping that it's a trap and he can use it to find Viktor. It's Stefan, who offers to tell Napoleon where Illya is in return for payment and a guarantee that he'll go free. Napoleon agrees, and Stefan says that he will meet him in person. He points out that he could kill Napoleon anytime and fires a shot into the glass, and Napoleon tells him to meet him in a nearby alleyway in five minutes.
Napoleon and Sheila wait in the alleyway, and Stefan comes in. The agent confirms that Stefan is unarmed, and Stefan demands his money first. Napoleon refuses to negotiate, and Stefan directs him to the second floor of a refrigeration plant. Viktor shoots Stefan in the back and the man collapses. Satisfied that Stefan was telling the truth, Napoleon leads Sheila off.
Viktor continues pursuing Napoleon, watching as he helps Sheila through the debris. They find the plant and it appears unguarded. Napoleon tosses a piece of debris at the fence and confirms that it's electrified, and starts up a nearby front-loader. They drive up to the fence and climb over the fence via the loader. They go inside the plant and narrowly avoid a falling beam, and come to a wooden door leading to a freezer. Napoleon opens it and finds a frozen corpse.
Viktor comes back and complains that Napoleon hasn't proven sufficient challenging. He's willing to settle and slams the door shut. Viktor then turns on the freezing unit and the gas starts pumping through the coils.
Sewer Rats and Alley Cats
As the temperature drops, Napoleon pounds on the door with the chisel but soon realizes that it's useless. He finds a conduit aperture in the wall and tries to hammer it open. Once he releases the gas, Napoleon blocks the hole and the expanding pressure blasts the aperture open so they can crawl through the enlarged hole.
As the sun rises with less than a half hour left, Napoleon and Sheila go out on the street Napoleon figures that Illya's only chance is for him to let Viktor come after him, then grab the hunter and force the truth out of him. The agent steps out on the street and calls to Viktor. When Viktor responds, Napoleon ducks into an excavation hole and Viktor congratulates him over the loudspeaker on his temporary escape. He invites Napoleon to continue, unaware that Stefan is still alive.
Napoleon makes a run for a nearby subway entrance to lure Viktor out. Viktor shoots at him from a rooftop, forcing Napoleon to retreat. As he boasts that he can enter the hunt at any moment, Napoleon pries up a manhole cover and he climbs down with Sheila.
Stefan returns to the gas chamber and Illya sees him through the glass. Dying, Stefan tries to walk over but collapses.
Napoleon and Sheila come to a dead-end in the sewers. Sheila spots a light from an overhead exit and panics when she sees a rat. Napoleon drives it off and they climb up to the street. Viktor is waiting and prepares to release Ving.
Stefan gets up and tries to open the chamber door.
Napoleon spots Viktor and tries to take cover.
Stefan reaches for the door latch
What's Good for the Goose...
Napoleon takes cover and Viktor realizes that he needs to reload.
Stefan opens the chamber door, setting off an air-raid siren alarm. Viktor hears it and tells Napoleon that he has to deal with Illya. He releases Ving to deal with Napoleon and heads for the chamber. Napoleon tells Sheila to follow Viktor and leave a trail with the emeralds in her necklace, while he takes on Ving. She slips away and Napoleon attracts Ving's attention. It bites his arm as they wrestle, and Napoleon manages to stab it to death with the chisel.
Napoleon continues through the streets, following the trial of emeralds. They lead to a wax museum, and Napoleon goes inside with only five minutes remaining. He goes downstairs and just avoids the trapdoor. Napoleon finds the gas chamber with one minute left and gets the door open. Viktor is behind him, using Sheila as a shield. He orders Napoleon to go inside and join Illya, but Sheila breaks free. Napoleon knocks Viktor down and unstraps Illya. Viktor grabs his pistol and Sheila hits him with a chain. Illya and Napoleon attack the man, knocking him into the gas chamber. The door slams shuts, and the agents are unable to get it open. The cyanide pellets release, and Viktor braces himself, remaining standing as long as he can before he dies from the gas.
Later, a tuxedoed Illya visits Napoleon in the hospital as Napoleon recovers from his arm injury. He takes great delight in echoing Napoleon's words earlier, and says that Sheila's father bought her an amusement gallery. Illya is taking Sheila to the grand opening. The nurse takes Napoleon's temperature, and Illya leaves, smiling, as Napoleon flirts with the nurse.