When the body of a college swimmer washes up on the beach, the team must determine if it was an accident or murder; Gibbs prepares for his first interrogation.

When Dr. Donald "Ducky" Mallard, a liaison from D.C. headquarters and an old acquaintance of Gibbs', arrives to evaluate whether Pendleton needs an in-house medical examiner, not everyone trusts that's the real reason behind his visit.