An investigation into weapons trafficking becomes personal for Tommy when an old friend becomes connected to the case. Meanwhile, Lockhart demands to see results from Kyle's probe into Frank's actions, which leads Frank to reveal some surprising information to his trainee.
Lockhart opens an internal investigation into a past shooting that could cost Frank his badge and freedom, which forces Kyle to help Frank clear his name or risk losing the one man who could help him solve his father's murder.
Frank's longtime friend and informant is killed by Yakuza assassins, and his quest for revenge puts him and Kyle at odds with an FBI agent whose operation against the Yakuza is jeopardized by Frank's actions.
The rift between Kyle and Frank grows when Kyle refuses to adhere to one of Frank's morally ambiguous rules, but the pair must put aside their differences when they learn the notorious hit man known as El Cucuy is targeting members of the Russian mob in Los Angeles.
Kyle grows concerned that Frank's rogue tactics will put a kidnapped girl's life at even greater risk after a former member of Muammar Gaddafi's Amazonian Guard becomes involved in the deal and ups the stakes for the girl's safe return.
Kyle Craig, an idealistic police officer, is partnered with morally ambiguous detective Frank Rourke in the LAPD. In the opener, Kyle is assigned to work undercover on Frank's team and report on his off-book methods. Meanwhile, Frank tutors Kyle in the way of the streets where the ends often justify the means.