The Boots are studying for their examination when they stop a robbery at a food truck. The next morning, Nolan wakes up next to Jessica and they talk about her new job at Homeland Security. He wants her to meet Henry but she seems unsure about it and Nolan can sense it.
Bishop comes to a decision on Officer Ruiz’s offer to become a “rat” inside the station house. Bishop tells her she is taking a different direction. She told Ruiz’s boss about the offer. It doesn’t end well for the IA officer. Bishop’s case is closed and an official reprimand is placed in her file. Bishop is grateful for the decision but knows what it means for her career.
It’s the day of the test for the Boots. Following the written exam they will have an oral exam in the chief’s office. Lopez feels West can pass the test but is considering requesting he get a new TO. She feels like has failed West. He doesn’t want things to change.
While Nolan and Bishop wait for homicide to show up to the scene of their murder victim, Jessica and a team of DHS and CDC personnel arrive. Their guy was part of a homegrown terror cell and DSH believes the group is planning a deadly biological attack on Los Angeles.
The victim, Corey Valance, arrived in LA with another man that DHS doesn’t know. Both belong to a fringe nationalist group that believes “LA stands for everything that is wrong with America.” It’s believed the partner killed Valance. The Feds believe Corey’s partner is working a local, the person who picked him at the bus station.
The biological is hemorrhagic fever. There’s an experimental vaccine with only a few hundred doses. The fever has a 90% fatality rate without treatment. So things are pretty dicey at the moment.
Nolan confronts Jessica about the potential attack. He figures she knew about it when she brought up Henry visit earlier: she was hesitant to talk about it. Jessica tells him she only found about last week about a potential threat and explains DHS and the FBi hear dozens of threats that are just chatter on the airwaves, nothing serious. He’s upset that she didn’t tell him.
Lopez can’t call Wesley to tell him about the treat. She doesn’t trust him. But the others tell their families about the threat and to avoid public spaces.
The Boots and TOs go to talk to passengers on the bus.
Nolan and Bishop talk to a guy who took selfies on the bus and has a photo of Valance and his partner.
Chen and Bradford talk to a man who grabbed the wrong bag. A bag with vials of hemorrhagic fever inside. The man is sick and he coughs up blood on Bradford. He slams the door on Chen to keep her safe.
Back at the station, Jessica apologizes to Nolan for not telling him about what was going on and wouldn’t put Henry in danger. The FBI enhances the photo and gets an ID on the partner: Jimmy Roskin. Sergeant Grey informs the team that they have their first infection: the man Bradford and Chen went to talk to.
The CDC asks Bradford to go through the bag. He finds a spray bottle inside. This is the mode of delivery for the virus.
They get a hit on the driver who picked up is in the wind but they know where he was headed. Patrol units fan out across nearby neighborhoods to find the driver.
Wesley confronts Lopez about what is going on. She places him under arrest to keep him quiet.
Bishop and Nolan talk to homeless man who has seen the driver. He points them to a house. The unknown man is Brandon Mitchell.
Back at the passenger’s house, Bradford watches the man die.
The team realizes that Mitchell may take the backroads to the airport where thousands are stranded because its shut down.
Bradford and Chen talk. She tells Bradford he’ll be okay. He tells her that he won’t go out the same way the passenger did. He will take his own life when the time comes.
The team tracks Mitchell’s car down. Noland and Bishop are in the lead, with Lopez, West and Sgt. Grey following. Nolan rams Mitchell’s car and there is a shootout.
Mitchell and his partners take off on foot. West and Lopez chase after Mitchell. THe suspect hops on the bus with the virus. West gets on the bus he’s working to get Lopez clear shot to take out Mitchell. Lopez takes out Mitchell but grazes West in the process. An unwritten rule states that she can’t have West reassigned because she shot him.
Nolan and Jessica search for the other suspect, JImmy. They track him down a house. They come under fire with another shootout following. The guy isn’t willing to give up. Nolan tries to talk to the guy by bolstering his ego. Jessica kills him. Nolan believes he was giving up but Jessica tells him the guy was going for a gun.
The vaccine arrives at the house for Bradford. He’s not showing any symptoms but gets it anyways.
Wesley admits he didn’t exactly understand what was going on and apologizes.
West and his dad make up.
Nolan is concerned that Jessica shot Jimmy on purpose. Bishop tells him to drop it.