A TV reporter accompanies a group of ATF agents on a raid of suspected gunrunners; on the deck they find the bodies of five civilian men, already dead, two of whom (career criminals) wear authentic uniforms of the US Marine Corps and bear counterfeit ID cards; Director Vance orders the Callen team to investigate. G and Sam find dead birds and squirrels; Eric and Kensi find telephone traces and a street address, which allow the team to meet Esther, a sweet elderly retired researcher in biological warfare, who now suffers from Alzheimer's disease. Esther tells about her...