Alexei is besotted with Pauline. In debt to the Marquis, Paulina gave money to Alexei to gamble for her, alas unsuccessfully. Her stepfather the General, Alexei’s employer, is enamoured with the adventuress Blanche and also indebted to the Marquis. His hopes rest on inheriting his grandmother’s fortune. The old lady arrives in Roulettenbourg unexpectedly, takes to the gaming tables herself and loses catastrophically. Blanche abandons the General. The Marquis releases Paulina from her bond. Alexei gambles to win Paulina affections, twice breaking the bank. When he excitedly presents her the winnings she realises his soul is lost and rejects him.