In summer 1945, American troops made a startling discovery in northern Germany: a secret hangar housing a dozen unfinished boomerang-shaped aircraft, the HO 229, Hitler's "stealth fighters." The "flying wings" were sent to the U.S., and today a team of hand-picked experts is working to reproduce a complete HO 229 in an effort to prove whether this Nazi-designed fighter predates the modern stealth by nearly four decades. Could it really have eluded Allied radar and changed the course of the war?