In Morocco a bomb explodes inside a nightclub while Ziva sings; in Washington, DC, Gibbs and his new gang investigate the death of a petty officer, Vargo, who died of a gunshot in his house trailer, without detection, four and a half months before. The team learn that a former buddy and shipmate, Roberts, died in the explosion in Morocco, and that Ziva sustained injuries; Gibbs speaks by telephone with Ziva, who says that Vance had tipped her about Roberts, who apparently was the target of the bomb. Vance tells Gibbs that an NCIS agent had blackmailed Vargo before he disappeared. After another shooting, Vance, Gibbs, and McGee reach a solution, and Ziva gladly returns to the NCIS.