On the front steps of a federal building in Los Angeles, a woman hands an envelope to a man, then a gunman, posing as an LAPD cop, shoots the man to death, and the woman makes tracks; the victim was an employee of the US Department of State and a major in the Marine Corps Reserve; Callen and company investigate. The woman, Jillian, is a nurse from a cosmetic-surgery center in Beverly Hills and the wife of the surgeon; a print at the scene identifies the killer as a terrorist; G and Sam, visiting the medical office, find the body of the surgeon; the photo on file for the shooter does not match the face at the scene; Sam suggests a facial reconstruction. Kensi and Deeks check out an upscale medical spa, where Deeks gets a dose of pepper spray. Eric plays show-and-tell. Kensi and Deeks catch Jillian; Eric and Nell decipher a clue, then G and Sam trace it; Kensi and Deeks go to a party, and Sam and Jillian join them; the team grab the bad guys and prevent any damage.