Having failed to win fame in the bullring, impoverished Juan Bautista goes to Barcelona, Spain, in the hope of making a name for himself as a singing matador. So persistent is he that impresario Francisco Carbonell agrees to give him a booking if, within three days, he can seduce the beautiful Olimpia, Barcelona's most celebrated "courtesan." Undaunted by the fact that the young woman has become wealthy by bestowing nothing more than promises, Juan poses as the trusted emissary of a wealthy count who is prepared to pay a fortune just to meet Olimpia on a platonic level. Intrigued by the proposal, Olimpia accepts Juan's check for 25,000 pesetas and consents to meet the count. But when he fails to appear at each of their scheduled meetings, Olimpia is obliged to pass the time with Juan. On the third day, she purchases a mink coat with the check and, lightheaded from too much wine, invites Juan to spend the night with her. In the morning, however, she discovers that the check was worthless. When Juan confesses his guilt, the enraged Olimpia forces him at gunpoint to bathe in a tub of blue dye guaranteed to last for two years. Although Juan has won the wager, he is too much of a gentleman to give Carbonell the details of his night with Olimpia, and he loses his contract. Sometime later, Olimpia and Matabosch, one of her wealthy conquests, see a poster advertising Juan as Spain's only singing blue matador.