How Did an ‘NCIS’ Team-Up Assist Mark Harmon in Writing ‘Ghosts of Honolulu’ with Leon Caroll Jr.?

Since retiring as Leroy Jethro Gibbs on NCIS in 2021, Mark Harmon has co-written a real-life espionage tale, “Ghosts of Honolulu,” with former NCIS special agent Leon Carroll Jr.

The book focuses on Douglas Wada, the sole Japanese-American agent in naval intelligence before NCIS. As war with Japan approaches, Wada, a former baseball prodigy, works undercover as a journalist, translating Japanese consulate wiretaps. Carroll describes Wada as a Gibbs-like figure—reserved, meticulous, and insightful.

The narrative unfolds against a backdrop of U.S. military intelligence, Nazi spies, and anti-Japanese sentiment. Tensions rise after the Pearl Harbor attack, as Wada questions America’s first World War II POW, creating a gripping storyline for fans missing Gibbs in the interview room.