Sam and Callen are back aboard the USS Allegiance with Special Agent Ehsan Navid, the ship's new agent afloat. Harm isn't there because he's testifying before a Congressional panel about the ISIS infiltration. Lt. Leslie Grant was found shot to death in Los Angeles. The Center for Disease Control puts the Allegiance under quarantine for possible exposure to ebola. Kensi and Deeks meet USAMRIID Col. Sandra Kaufman. They need to find Grant's killers to contain the ebola outbreak. A cargo container from Somalia had a man dead from ebola inside it and the ship it was on crossed paths with the Allegiance in Honolulu. Kensi and Deeks find the car that Grant was picked up by and there's blood on and by it, with a trail going into a warehouse. It appears Grant was infected with the hopes of causing an outbreak, but she fought back, escaped, but she got shot. People on the Allegiance seem to be exposed. Kensi tells Deeks she's late, which is why she hesitated to enter the warehouse. Deeks and Kensi tase Jenny, who was the person who kidnapped Grant. Nell and Fatima identify Petty Officer Stephen Lamb as a possible ISIS sympathizer who is potentially exposed, but he collapses when Ehsan confronts him. Lamb tells Ehsan he mistakenly befriended an ISIS sympathizer. Jenny's partner is carrying ebola. Jenny tells Kensi and Deeks they injected Grant after she get off the ship. The target is a VA hospital. Fadel Ali is Jenny's partner. Deeks and Kensi corner him at the hospital, and he takes a nurse as a hostage. Deeks shoots him before he can inject her. The ship's outbreak was judged to be psychomatic. Lamb apologizes to Ehsan for his dislike for Muslims. Kensi tells Deeks she's not pregnant.