The Pursuit is Plan Z is the unlikely origin story of the intelligence coup that led to the largest naval battle in history, in World War II's Pacific Theater, resulting in the most crushing defeat the U.S. Navy has ever inflicted on an enemy force.

In March 1944, the Japanese admiral in charge of the Combined Fleet of the Imperial Navy departed the Palau Islands, bound for the Philippines. With him was a secure briefcase containing the location and numbers of every single Japanese aircraft, ship, sailor, and soldier in the Pacific. Dubbed War Plan Z, the documents detailed how and where the Japanese would counter-attack any American offensive.

En route, Admiral Fukudome’s flying boat got lost in a storm and crashed off the coast of Cebu. The admiral survived, as did his briefcase. Both were captured by Filipino guerrillas, who brought them to their commander, American insurgent James Cushing. Recognizing the value of the intelligence, Cushing made plans to smuggle Fukudome and the documents out of the Philippines and into the hands of General MacArthur’s special operations department. Japanese forces unleashed a wave of wanton violence, burning a path of destruction deep into Cebu’s central mountains in search of their captured admiral.

Cushing knew the real value wasn't the admiral, but the war plan—and the Japanese were not yet certain the insurgent had found the briefcase. But soon after Fukudome was released, the chase was back on after a captive confessed Cushing possessed War Plan Z. What followed was one of the war’s most epic pursuits, a deadly game of cat and mouse through the Philippine Islands to get Plan Z to a special operations USN submarine. The course of the war’s final year would be determined by who won this race.