Vance gives Tony a sensitive assignment to escort an admiral's daughter, Amanda, from Marseille, France, back to Washington, DC; meanwhile Gibbs and the others investigate in Norfolk, Virginia, where a plumber discovered a body inside a septic tank in off-base military family housing. When Tony arrives at the field office of the NCIS in Marseille, he meets the local gendarmerie, who take special interest in him -- because someone has shot and killed all five employees of that office. Tony finds Amanda at a night club and persuades her to go with him, then a French woman cop pulls a switch, and another man dies. Tony and Amanda catch a ride aboard a party bus. Gibbs and Abby find a link between Amanda and the guy from the septic tank; Vance and Gibbs take the admiral to the chat room. Tony figures out Amanda, so they talk about that, then they return to Marseille, find a mess, get help, wind it up, and return to Washington. Jimmy receives a special message.