A few episodes ago, Kim Burgess revealed that she was finally moving on from Ruzek and dating someone new.
Of course, in cop terminology that means she's still dating someone working in the same field. And as we all know, those never work out.
We meet her new guy Matt and a gala honoring the work that the Chicago PD does.
Soon after, a Congressman is being investigated for the murder of a Russian escort.
He swears he's innocent and his account of the night takes a rather weird turn. He was drinking at the bar when a foreign woman approached him. He doesn't remember much from their conversation nor does he remember going upstairs with her.
The next morning, he woke up to find her dead in his hotel room.
Voight and team check out his story and realize that even though it sounds absurd, he's telling the truth. He was being set-up.
Further investigation reveals that the Odessa Mob, run by a Ukranian man, had been offering modeling contracts to young girls in Russia.
After they were brought to the States, they were held hostage and forced to work as escorts and steal belongings from rich white men at luxurious hotels.
The girl, Sasha, was killed because she was trying to escape the mob.
Her mother who was hoping to help rescue her was also found shot but she thankfully survived and was able to provide Voight's team with a picture of the suspect.
Burgess recalls Matt mentioning that his big case, which he's been working on for two years, involved taking down the Odessa Mob.
She naively goes to him to see if he will help her identify the suspect.
Matt refuses to cooperate and advises that they set up a meeting with their higher-ups.
When she tells Voight, he's livid. Apparently, the FBI and the CPD do not have the same goals, ever.
During the meeting, Matt and his boss tell them that they cannot give up the identity of the suspect because he's vital to their investigation. And they are so close to locking these guys up once and for all.
However, that doesn't sit well with Voight because he's all about justice and he knows that they'll offer Yuri a plea deal and he'll get off serving little to no time.
Instead, he forces Burgess to make a choice — us or them.
Burgess is torn because she really likes Matt but Intelligence is her family too.
She turns to ex Ruzek for advice but he tells her that neither choice is ideal; she's going to have to go with her gut.
The next day she meets up with Matt and sets him up. Within the hour, Intelligence tracks down and arrests Yuri at his FBI-provided hideout.
Burgess feels terrible about screwing up the biggest case of Matt's career and as you can imagine, he's not very understanding.
Meanwhile, Voight is forced to ruin an innocent man's life by turning over crime scene photos to Price, who threatened to out another secret if Voight didn't repay the favor he owed him.