The body of a former Marine lieutenant is found hidden under an 18-wheeler. Jack says Vance is concerned about how Ziva's visit has affected team morale. Jimmy finds ceramics under the truck, which form a garden gnome when assembled. The victim is Elijah Buck. McGee talks with Jack about Bishop. Gibbs and Bishop talk to the victim's brother, Peter, at their mobile-home park. They find from where the gnome had been stolen, which proves to be the crime scene. Lou Jinks, a resident, starts running. Gibbs discovers a stockpile of guns in his unit. Jinks points a finger at property guru Mike Midas, who got the Buck brothers involved with the mobile-home park. Bishop tells Jack she's worried about Torres. Peter got a note saying "You're next." He says Esther Daniels is the ringleader of the tenants. Torres tells Jack that he let Ziva win. He thinks Jack and GIbbs have a relationship outside work. Someone hit Peter's car with a Molotov bomb. Ducky found out resident Vince Pierman was in witness protection after turning state's evidence against a crime family. Vince suffers an asthma attack. Gibbs confronts Jack about what she's up to. Jack wants to talk about him and Ziva. He admits Ziva's coming and leaving bothers him. Jack tells Gibbs he needs to let Ziva go again. The trailer park land is laced with toxic chemicals. Gibbs uses Ducky to interrogate chemical-company executives about a warehouse fire upriver of the park. The chemical company used the Buck brothers to buy the park. They were supposed to buy out the tenants, but instead they kept the money and raised the rent to force out the tenants. Peter killed Elijah to keep him from telling the tenants. GIbbs replaces Jack's inkblot with Esther's elephant painting.