It is Paris, 1911. The Mona Lisa (aka La Joconde) has just been stolen from the Louvre and is on the front page of papers around the world. Both Pablo Picasso and noted writer and critic Guillaume Apollinaire are called in for questioning by the police. (This is all true.) Little do they know, the real thief, Vincenzo Peruggia, who happens to be a friend and neighbor of theirs, has it hidden in his apartment. When Apollinaire gets threatened by a gangster to whom he owes a large gambling debt, Vincenzo reveals to them, and to Apollinaire's paramour, the painter Marie Laurencin that he is the thief. They then conspire to paint a forgery of the painting to pay off the debt. Aided by a Parisian art restorer, Marie paints an identical Mona Lisa. In a final farce scene the two paintings get mixed up. It is a show about the meaning of art, friendship, gambling, and forgery – with 20 very catchy songs.