William Newsome, an ATF agent, breaks into a warehouse searching for something in a shipping container. When confronted by three guards, he sets off a grenade in the container and takes out the trio. Callen and Anna struggle with the seating arrangement for the reception. Sam and Richard practice sparring. Kensi suffers food poisoning from Deeks' leftovers. Rountree's sister Jordyn has a medical-school interview. Kilbride meets with ATF SAC Kerry Adams. Newsome is missing check-ins and Adams fears he may have turned. She wants OSP to investigate him and his activities. There's been movement in Rountree's civil suit against the LAPD but he doesn't want Jordyn to get distracted. Sam and Callen meet Newsome and will look into the gunrunners and where they are getting their military weapons while Deeks and Kensi provide overwatch for Newsome. Rountree discovers Newsome's daughter attends a fancy college and drives an expensive car. Nina Barnes offers Callen marital advice. Nina says that the gunrunners receive great intel. Kilbride fills in Kensi and Deeks concerning the suspicions about Newsome. Trying to help a stressed Anna, Arkady lines up a big-time, expensive DJ for the wedding. Richard has wandered and calls Sam from the park, pulling him off the case. Newsome's daughter is paying for school with a college account set up by her grandfather. Fatima and Rountree look into other law enforcement agents involved in the case. Two big vans approach the house being watched by Kensi and Deeks. Sam doesn't understand why Richard is dead-set against participating in a drug trial. Sam convinces him to try. A gunrunner soon regrets attempting to attack Newsome. On a hunch and without a warrant, Fatima determines that Adams is dirty. Callen and Sam cut off Adams and the gunrunners' leader but find themselves outgunned.