Moments after Simon flees with the antidote, Sophia and her men subdue Leila. Leila blames Sophia for killing her father but it's clear Sophia is very upset by his death. Dr. Lu arrives moments later and tells Sophia that Michael stole the antidote. Sophia realizes that Simon has escaped with the antidote and it's only a matter of time before people learn about the Sleeper community. It must be evacuated at once. While Christina sits by Martinez's side, Jarvis meets with Peel to discuss a replacement for Sterling. Sophia phones Jarvis, interrupting the meeting. She tells Jarvis that Simon will attempt to save Martinez using a "counteragent" antidote. She tells Jarvis he must stop Simon. If Martinez recovers, Jarvis will be in jail for the rest of his life.
Sophia and Dr. Lu in an underground bunker Vicky tells Sean she thinks they should phone the police about Sophia's plan. Sean reminds Vicky that Sophia obviously has connections high up in the U.S. government; calling the police won't help. They continue to search for the vehicle carrying the infected lungs. In an underground bunker, Carlos tells Sophia that conditions on their home planet are worsening. They've got to make room on Earth immediately. Dr. Lu tells Sophia that they have a problem: in order for a pandemic to spread, the host has to survive long enough to spread the disease. This strain might act too fast; after all, the man operating on the infected corpse died immediately. Dr. Lu needs more reliable data on the virus, and Sophia chillingly tells her another "field test" is in the planning stages.
At his home, Sterling pulls a gun on an intruder. The intruder turns around; it's Simon! Simon claims he has the antidote that can save Martinez. He says he's split with Sophia for good. Sterling has his doubts, but Simon manages to convince Sterling that his intentions are good. They notice a sedan outside and realize that Jarvis is having Sterling followed. In that moment, Sterling realizes that he and Simon are in this together. In the sedan, Agents Garret and Beal spot Simon in Sterling's home. They phone two other agents and surround Sterling's home!
Meanwhile, Sean and Vicky continue to track the rental car carrying the deadly virus. They find the car in the parking lot of a shopping mall! In the trunk, Sean and Vicky find blueprints of the mall, but not the silver suitcase carrying the virus. Looks like Sophia's "field test" will put hundreds of innocent civilians in danger. On the roof of the mall, Alex opens the suitcase and reveals the infected lungs!
Outside of Sterling's house, cops surround the federal agents! The cops force them to disarm, not realizing they're on a covert operation! It's clear Simon and Sterling called 911 and reported an armed robbery! By the time the cops realize their error, Simon and Sterling have already escaped. Jarvis calls Sophia and tells her that his agents weren't able to capture Simon and get the antidote. Worse, Agent Lee and Sterling are working together. Enraged, Sophia says that if Martinez survives and returns to the presidency, the alliance between Sophia and Jarvis is off. Sophia had promised to spare American lives, but if Jarvis can't hold up his end of the bargain, the deal is void.
In a stolen car, Sterling and Simon think of how to get the antidote to Martinez. The only way to save Martinez is to somehow get the antidote to Christina. At the hospital, officers stop Christina from visiting her ailing husband, claiming it's a restricted area. Clearly, behind the scenes, Jarvis fears that Christina will find a way to help her husband. Later, an agent tells Jarvis that they've recorded a 24-second phone conversation between Christina and Sterling. The call was encrypted and will take a couple hours to decrypt. Jarvis tells his assistant to track down the First Lady at once.
At the mall, Sean and Vicky try to locate Alex and the infected lungs. On the roof, Alex attempts to spread the virus through the mall's ventilation system. Meanwhile, Vicky tells a security guard that he must evacuate the mall at once. When he hesitates, Vicky pulls a gun on him and tells him to take action. Meanwhile, in the surveillance room, Roman sees that Sean Walker has entered the mall. He tells Sophia the bad news, and she replies that Roman must stop Sean from interfering. Roman chases Sean onto the roof and a shootout ensues! Roman yells to Alex to continue working; he'll take care of Sean.
Jarvis tells Christina that there must've been some misunderstanding; of course she can visit her ailing husband. Then Jarvis tells Christina that Martinez didn't have a stroke; he was poisoned. Jarvis claims that Simon and Sterling were the ones who tried to kill Martinez. Jarvis manages to convince Christina so she tells him a secret: Sterling reached out to her only moments before and they were planning to meet secretly at a warehouse. Jarvis thanks Christina for the private information and vows to stop Sterling and Simon.
Sophia asks Leila what she told Sean Walker. How much does he know about the Sleepers' plan? Leila refuses to tell Sophia anything. Sophia assures Leila that Sean will die, just like Michael. Meanwhile, on the roof of the mall, Sean and Roman fire at one another while Alex attempts to spread the virus. Downstairs, Vicky forces the security guard to sound the alarm and evacuate the mall. After most of the civilians have been evacuated, Vicky appears on the roof and shoots Roman dead. Then Sean and Vicky look for Alex, but she's gone. She's left behind a pressurized tank that will disperse the virus in a matter of seconds!
At the White House, General Armbruster shows Jarvis and his staff surveillance footage of Simon and Sterling at the warehouse. When Peel states that he finds it hard to believe that Sterling could be participating in traitorous actions, Jarvis snaps at him. Regardless of Peel's suspicion, Jarvis plans to go through with an air strike that will decimate that warehouse and kill Simon and Sterling while they meet inside. When Armbruster objects to the harsh military action, Jarvis overrules him too. Moments later, the drone fires a missile at the warehouse! It explodes into flames, while Peel and Armbruster look on, shocked.
Alex leaves the mall and boards a city bus. On the roof of the mall, Sean and Vicky finally manage to freeze the timer and stop the virus from being released. Now they've just got to find that suitcase and the remainder of the infected lungs! At the underground bunker, Alex arrives with a bus full of dead bodies - all victims of the deadly virus. Sophia is pleased because now Dr. Lu can study these bodies to learn more about the virus. Later, Dr. Lu tells Sophia that the virus kills humans too quickly, but if Sophia can infect a hybrid, the transmission will be slow enough to spread across whole populations. Sophia gets the message: the key to spreading the virus is infecting Leila.
Agents search the burning embers of the warehouse but see no sign of Sterling or Simon. They've managed to evacuate through a tunnel in the ground! Jarvis' men bring him the decrypted phone conversation between Sterling and Christina. Jarvis realizes that Christina and Sterling were working together; the warehouse story was just a diversion so Simon could get Christina the antidote! At the hospital, Christina injects Martinez with the antidote! Back at the underground bunker, Sophia injects Leila with the virus. Because Leila's a hybrid, she'll be the perfect bridge. In no time, she'll help murder millions of innocent lives.