The episode opens with Nolan and Bailey continuing their cop versus firefighter debate. Lopez is back from maternity leave, showing pictures of Jack to the other officers in the office.

Smitty is nominated to be a union rep, though he is the only one running for the position. Chen and Bradford drive together for the day, she finally gets to be his "gopher".

Wesley goes to speak with Elijah, debating how he can defend the client Elijah gave him with such incriminating evidence. Wesley hides in the kitchen as Grey shows up to have a word with Elijah.

Nolan answers a call regarding a bipolar woman running out of her house from her husband and health care aide. A neighbor calls authorities as it looked like the wife was running away from something and did not want to return to the house.

Wesley runs into an old friend, one that stood up for him during all of his drama. She asks to hang out with him later that night.

Nolan continues to look for the bipolar woman, finding her in an alleyway. It's revealed that she does not speak English, though things are suspicious as she's scared of her supposed husband.

This provokes the supposed husband and health care aide into a gunfight with Nolan; proving that everything is not as it seems. Nolan lets the woman out of the car in an attempt to help her, though she flees at her first chance.

Chen and Bradford arrive to give Nolan backup after the suspects also flee the scene. The three enter the house, only to discover they are not investigating human trafficking but rather have stumbled into a Russian safe house.

Wesley meets with his client, suggesting that he should betray Elijah. Lopez interrupts by asking Wesley to drop her breast milk off at home because the work fridge is broken.

The feds show up to help Bradford, Nolan, and Chen with the investigation. Chen lies and says Bradford told them not to touch the scene and simply "secure it".

Nolan hints at how he wants Harper to run for Union Rep. The team finds out the identity of the missing woman, as well as finding her boyfriend.

Her boyfriend is an Air Force major who doesn't show up to work the day she goes missing. The team finds her boyfriend murdered in his own home, the feds show up again.

They discuss the case with the feds and it is revealed that the woman, Katerina, is a Russian spy who went rogue.

Lopez ID's the biker who was hit by a car and kidnapped, revealing to Harper that she believes this incident is connected to the serial arsonist and killer they have been tracking.

Chen and Thorsen have a heart to heart after he bails on his friend after she is revealed to be using him for followers. Though Thorsen hits a tender nerve with the mention of West. The two begin to form a solid friendship full of trust.

Harper is investigating for Lopez and spots a possible suspect after sending dispatch her location and the plates of the car. She comes across a body, only for the suspect she spots earlier to set a fire in an attempt to trap her and the other body.

Bailey and Nolan wait for Harper at the hospital. Harper ends up being okay, though Lopez grabs a statement from her.

Nolan discusses his day, including Katerina, only to have a breakthrough after joking around with Bailey. The two go back to the car and search for something that Nolan believes Katerina left behind.

Katerina ambushes them and holds a gun to Bailey's head. In exchange for Bailey's life, Katerina wants the flash drive that Nolan found in his patrol car.

Elijah had Wesley's client killed, citing that the "word on the street was that he was going to turn on him". Wesley begs for forgiveness and digs himself a deeper hole by swearing on his family's life.

Nolan is encouraged to run for Union Rep by Lopez, and he follows through.