Don Winslow of the Navy #16

Don Winslow pursues the Japanese war ace Tom Toguchi, known as "The American," who possesses a stolen locket containing secret coded naval information that must be delivered to the Japanese Fleet Commander. After a fierce battle involving pirate ships and Spanish forces in a colonial setting, Don Winslow manages to recover the locket and thwart Toguchi's escape. The story culminates in Tokyo, where Emperor Hirohito himself commends Toguchi for his efforts, though the American's mission ultimately fails as Don Winslow secures the vital intelligence for the United States Navy.