Mia Verhag loses her job as a chorus singer when she rejects the advances of the theatre director. While she is in the grips of despair, she encounters the millionaire Roswolsky, who takes her to his luxurious house and gives her a key to the garden gate, allowing her to visit the surrounding park whenever she pleases. This chance meeting sends rumours flying everywhere, and soon Mia appears on the front pages of all the newspapers as Roswolsky’s mistress. The city’s merchants and creditors compete to lend her money, and she lands the leading role in the theatre’s new production. There, she falls in love with Count Albich – but, believing the rumours, he avoids her. Mia follows him to Monte Carlo, while Roswolsky himself falls genuinely in love with her and plots to take Albich out of the running. A grand drama is set to unfold.