Rick Dotson, an arms dealer, is murdered. Arkady and Callen visit the imprisoned Anna. She tells them both not to come back because she's going to be inside for a long time. Sam chats with Ochoa, who comes from just up the road in Oxnard. The team is investigating Rick's death. Sam invites Eric to come along with them. Kensi tells Deeks that she's buying her dress from Brides Against Breast Cancer. Rick was taken out by a professional, who swam into the property. Sam and Callen suspect he has special-forces training. Rick's girlfriend Karen gave Kensi and Deeks photos of three men Rick about whom he had been warned. Sam chases down one of them, Lance Hamilton, on a motorcycle. Tom gives Sam and Callen background on Hamilton. Hamilton is working for the State Department. He tells them Dotson is the fourth high-level criminal killed in recent months. Daniel Aquilar becomes a suspect. His ex-wife Casey didn't know he'd left the service 20 months ago. She tells how their son William was killed in a drive-by shooting recently because a drug dealer lived next door. Deeks and Kensi check out Aquilar's storage locker, but they just missed him. No one blames Aquilar for what he's doing. Michael Whittaker, a cocaine dealer, is suspected to be his next target. The team plus Hamilton breaks up Aquilar's assassination attempt. Sam and Hamilton try to talk Aquilar into surrendering. He points his gun at Sam, who kills him. Sam blames himself afterward, although Callen tries to talk him down. Sam goes to tell Casey that Aquilar didn't make it and she's hysterical. Hamilton and Sam commiserate about losing their spouses. Hamilton invites Sam to join him at State. The judge sentences Anna to seven years with parole possible after three.