When criminals kidnap her brother and force her to secretly exchange their counterfeit dollars for real ones, bank cashier Rosa looks to an unassuming office boy named Julio to help her pull it off. But Rosa's buttoned-up bank manager boyfriend can't help but notice that something suspicious is going on, so he resolves to get to the bottom of it. Armando Silvestre, Irma Dorantes and Carlos Montesco star in this classic crime drama.