Hapless orchestra player becomes an unwitting pawn of rival factions within the French secret service after he is chosen as a decoy by being identified as a super secret agent.

With "little captain" Cambrai raising serious doubts about the reality of the so-called "super spy," Colonel Toulouse kidnaps Christine and forces Francois to play again the character of "The Tall Blond Man with One Black Shoe" in some fake adventures. All this to stop the investigation into the death of Colonel Milan.