The team is in a firefight. Sam gets hit in the leg. The survivor, Miguel Reyes, gives up the name of the weapons broker he was working for: Spencer Williams, Mosley's ex who took her son Derrick. Mosley takes over the interrogation. She demands to drive him to ATF. Callen assigns Kensi and Deeks to follow her, even though they're in the dark about her son. She takes him to a nondescript industrial building. Mosley gets a phone number from him after working him over. Callen argues with Hetty and Sam about Mosley's tactics. The phone belongs to a Mexican general, Arturo Vasquez, and she orders Eric to tap the phone, without a warrant. Callen tells Kensi and Deeks about Derrick. Deeks gets into a heated argument with Mosley and she fires him. The tap on the phone confirms WIlliams is working with Vasquez. Hetty tells Mosley to slow down. The wounded Sam is planning a raid for a small OSP team. A recording reveals Derrick's voice in the background, so he's at Vasquez's compound. Callen convinces Mosley to stay behind. Kensi and Deeks argue about Mosley's situation. Mosley has Deeks escorted out. Deeks tries to convince Kensi to agree to get out of NCIS soon. Kensi can't agree to leaving or to having kids. Deeks talks about calling off the wedding. Hidoko goes down on her own to do reconnaissance. Hetty threatens to ground the plane rather than let Callen, Sam and Kensi go on the mission. Mosley threatens to bring down the team if Hetty does that. Sam's bandage keeps leaking. Deeks joins them on the mission.