Honorin is the simple and naive stage manager of a traveling theatre troupe, whose one ambition is to once play the role of the cavalier in the opera "Francis I, or the Loves of the Beautiful Ferroniere". A hypnotist puts him to sleep and in his dreams he is transplanted to the days of the Renaissance. There, among other items, he is made a Duke by Henri VIII, fights a duel and survives a series of medieval tortures, while also bestowing some 20th century blessings on the court of Francis I.

A hero of the Paris streets is recruited for a conspiracy against Mazarin in the court of the King, but he reveals the subversive plot to Anne of Austria.