Author Stephen Hunter's series character Bob Lee Swagger, the ex-marine sniper who gained the nickname "Bob the Nailer" for his wartime exploits in Vietnam, has few soft spots. One is his late father, Earl, who was awarded the Presidential Medal of Honor for valor on Iwo Jima.
So when Philip Yano, a retired colonel in the Japan Ground Self-Defense Forces, requests Swagger's help in locating the sword that Yano's father carried into battle on Iwo Jima, the two form an immediate emotional bond.
Swagger succeeds in tracking down the sword and flies to Tokyo to return it. But Yano's sword, it seems, has a dark history, one that certain people are willing to kill for, and what started out as mere modern-day mayhem metamorphoses into a resourceful retro-telling of Japan's most famous vendetta, the tale of the 47 Ronin.