Although Janine is an extraordinarily talented dancer in a musical revue, she has no chance against her colleague Yvette, whom the director of the "Moulin Bleu" --- the variete they're both employed with --- has the hots for and who does everything to further her career. One day, Janine gets to know the Count Rene, a rich Bon Vivant, who has arrived in Paris to join a renowned music publishing firm. What Janine does not know, however, is that this Count Rene is in reality a poor, unknown composer named Pierre, who has switched identities with the real count, so that the nobleman can tomcat around Paris at night getting his fill. In his new identity, Pierre has succeeded in introducing his newest work with success to the music publishers, thanks to his phony identity. The piece is even going to be performed in the "Moulin Bleu" and Janine, who in the meantime has gotten to know the truth about Pierre, is supposed to play the main role. Envious Yvette, however, wants that part and she'll do anything to get it ... and we mean, "anything".