An American traveling in Europe suddenly disappears, and his daughter, married to an eminent scientist, receives a letter asking her to go to Antwerp, which she does with her young son. Both are about to disappear. OSS 117 is asked by his superiors to solve these mysterious disappearances.

Antoine Espérandieu, a French tenderfoot, lands in Windows Canyon, Arizona, a remote place under the thumb of dangerous outlaw Dynamite Jack, only to discover the friend he was to meet there has been murdered. Worse, it is not long before Antoine realizes he is Jack's perfect lookalike. All the same, he decides to settle down in the small town, where he becomes the local tax collector. One day, he finds himself face to face with the bandit...