NCIS Special Agent Jessica Knight defuses a situation with a man, Petty Officer Toby Withers, holding a gun on his wife. When Withers releases his wife outside and the REACT team goes in, the house blows up. NCIS investigates the crime scene. Inside the house, they uncover Knight alive, thanks to the high-tech body armor she is wearing. Marcie drops by to visit Gibbs. She is following up on a file she dropped off for him to read. She wants him to help her find the true killer of her friend Hannah. Torres and Bishop discover Knight trying to escape from the hospital. Kasie discovers the explosive was detonated remotely by cell phone. Knight shows up at NCIS headquarters, inviting herself onto the investigation. She attempts to claim Gibbs' desk. McGee agrees to let her work the case for 48 hours. The armor's manufacturer, Peter Kessler, could backtrace the signal that detonated the bomb. Torres and Jessica just find the dead body of Richard Soren there. But there were also photos of the whole REACT team. Jessica convinces Vance to let her stay on the case. Gibbs discovers more details about the murder of Marcie's friend Hannah. They find two other murders with similar methods, indicating a serial killer. Palmer talks Jessica through her survivor's guilt. Kasie proves that Edward Madden, one of the dead REACT agents, was stealing and selling weapons. Madden's body armor was killing him. Madden wasn't stealing armor. He was gathering evidence against Kessler. REACT Supervisory Special Agent Tom Dalton, in league with Kessler, hired the bomber Soren, who detonated the bomb too soon. Jessica stops Dalton from jumping off the roof and arrests him. Everyone turns out for the funeral, including Gibbs at a distance. McGee subtly invites Jessica to join his team.