A court-martialed army captain infiltrates those spying for the Japanese in Panama and by himself wipes them out.
In November 1941 Rick Leland (Humphrey Bogart) is dishonorably discharged by a court martial. He knows artillery but is rejected by the Canadian army. Rick books passage on a Japanese ship going to Panama. On board he meets Alberta Marlow (Mary Astor) and sociologist Dr. Lorenz (Sydney Greenstreet), who wants the U. S. to keep the Philippines. On deck Rick kisses Alberta, and she gets seasick. Rick drinks with Dr. Lorenz and admits he served in Panama.
In New York Rick is followed, loses him, and reports to Col. Hart, who warns him about Joe Totsuiko. Rick sees the man who followed him with Alberta and hits him. Rick follows a man with a gun, and on the ship stops him from shooting Dr. Lorenz, who gets the Japanese captain to have the man shot. Joe Totsuiko (Victor Sen Yung) befriends Rick. Alberta says Oki is a different man, and Rick jokes with him. Dr. Lorenz asks Rick about his army troubles and gives him money for information on installations; Rick agrees. Alberta is sun-burned, and Rick says he got money from Dr. Lorenz. Rick learns about judo. Captain Higoto says they must take another boat.
At a hotel Rick asks Sam (Lee Tung Foo) to help him. Dr. Lorenz asks Rick about batteries and patrol planes, offering $1500 if he can find it that day. Rick reports to Smith (Charles Halton) in a bank and asks for the schedule, which they can change. Rick asks about Dan Morton, whom Alberta mentioned. While drinking, Alberta tells Rick she was followed. He asks her to work with him for Dr. Lorenz. Joe sits down with them. Alberta gets a call and leaves. Rick gets a key from Sam and searches Alberta's room. Dr. Lorenz comes in and tells him not to romance her. Rick gets $1500 and asks for $500 more. Dr. Lorenz says he doesn't need the information but pays Rick $1,000 as Joe knocks out Rick. Dr. Lorenz sees planes and checks the schedule.
Rick comes to and calls Smith to change plans; but Smith is shot. Rick tells Sam he was beat by Dr. Lorenz and gets a gun to attend a Japanese movie. Oki tells Rick to go to a plantation and is killed leaving. Rick escapes and takes a taxi. He sees a plane being prepared but is captured and taken to Dr. Lorenz, Alberta, and Joe. Dan Morton is drunk, and Rick learns he is Alberta's father. Rick gets a gun and with a machine gun shoots the plane as it is taking off so that it crashes; then he kills others. Rick and Alberta find Dr. Lorenz in the house, asking to be shot; but Rick says he is taking him to military intelligence.
This film was originally to be about plans to attack
Pearl Harbor; but after that event was not prevented, it was changed
to the Panama canal, indicating that an attack on these targets