A team of special agents, operating outside the military chain of command, must investigate any crime with pieces of evidence connected to Navy and Marine Corps personnel, regardless of rank or position. Character-driven stories with surprising twists play a large role in the second season of NCIS (Naval Criminal Investigative Service). The NCIS team of investigators is led by Special Agent Leroy Jethro Gibbs (Mark Harmon), an experienced investigator with sometimes unorthodox, but always-effective methods.