An NCIS team, led by Special agent Paula Cassidy, receives a tip about terrorist activity but it turns out to be a trap, resulting in the death of two agents. Cassidy, grief-stricken, begins blaming herself for what happened. Gibbs and his team are sent to investigate the deaths with Cassidy joining them during the investigation. While Ducky is sure that the man who Cassidy received the tip from was dead at least one day before the explosion even happened, Cassidy and Abby insist otherwise.