After being dressed down in a court-martial and dishonorably discharged from the United States Army in December 1941 for misappropriation of funds, Lieutenant Rick Leland (Humphrey Bogart) tries to get into the Canadian Army but is blacklisted. Deciding to take a Japanese boat via the Panama Canal to China, Rick meets lovely Alberta Marlow (Mary Astor), a slightly mysterious woman travelling alone whom he immediately falls for. He also meets the rotund sociologist Dr. Lorenz (Sydney Greenstreet) whose Japanese connections are far more involved than normal. When on one particular night Rick saves Lorenz from an assassin's bullet, the good doctor begins suggesting that the ex-Army man may have valuable information to sell to the right people for the right price. Leland delivers the goods but is waylaid by Lorenz' henchman, and recovers just in time to get to a mysterious plantation where some harsh anti-American activities against the nation are in motion. Along the way he runs into happy-go-lucky Joe Totsuiko (Victor Sen Yung) who's a little too friendly for the wrong reasons and Rick discovers why Lorenz, Alberta, and a host of Japanese operatives are convening in a desolate location and finds he's in for the fight of his life.