Early one morning, Marcos observes Juan successfully pulling off a bill-changing scam on a cashier, and then getting caught as he attempts to pull the same trick on the next shift. Marcos steps in, claiming to be a policeman, and drags Juan out of the store.
Once they are back on the street, Marcos reveals himself to be a fellow swindler with a game of much higher stakes in mind, and he invites Juan to be his partner in crime. A once-in-a-lifetime scheme seemingly falls into their laps - an old-time con man enlists them to sell a forged set of extremely valuable rare stamps, The Nine Queens.
The tricky negotiations that ensue bring into the picture a cast of suspicious characters, including Marcos' sister Valeria, their younger brother Federico and a slew of thieves, conmen and pickpockets. As the deceptions mount, it becomes more and more difficult to figure out who is conning whom.