NCIS:LA works alongside an LAPD task force to retrieve Semtex explosives stolen from a Marine warehouse when Deeks, trying to protect a female civilian from an Aryan thug, shots and kills him. Deeks thought the thug was going for a gun but it turns out the he was unarmed and LAPD soon breaks ties with NCIS, requiring Deeks to leave our team. Kensi is taking it the hardest, determined to clear her partner of any wrong doing. Meanwhile, Callen and the team believe there is evidence to suggest a mole in the LAPD. They think the mole assists a known gangster, Fisk, in evading any chance of LAPD building a case against him. Fisk is planning on selling the Semtex explosives to the Aryans and our team works to find the mole while Deeks feels the heat of Internal Affairs investigator, Quinn. Deeks old boss, Bates, is suspected of being the mole until Nell finds evidence that Quinn is on Fisk's payroll. Callen and the team, with Deeks seemingly working independently, rush to takedown Quinn and stop Fisk's transfer of explosives to the Aryans. Kensi finally finds out the truth that Hetty and the rest of the team knew Deeks killing of the Aryan was staged in order for him to infiltrate the LAPD. They needed Kensi to truly believe he was off the team since Bates, who was their suspected mole, was an expert interrogator and they knew he would question Kensi to see if Deeks was really off the team.