Plot

When her surrogate father who owns the casino she works in gets murdered, Modesty Blaise takes on those that killed him and are now at the casino to rob it. It turns out she is more than just a modest worker.

Modesty Blaise (Alexandra Staden) is working as a croupier in a casino in Tangier. A group of violent criminals assassinate her employer Henri Louche (Valentin Teodosiu) and enter the casino shooting staff and demanding entry to the casino's safe. Modesty delays her retaliation and retribution as she protects the lives of her staff. Modesty was very fond of Henri as he had taught her how to fleece a customer and reel him in. Making the customer win on small bets to make them feel lucky and then reeling them in on the big bets to clean them out. Raphael Garcia (Raymond Cruz) is the head of security at the casino. Irina (Eugenia Yuan) is a waitress.

Henri was killed on his way home and Raphael left the casino early to be with his wife. Modesty was in charge when the criminals enter the casino.

When the criminals, led by Miklos (Nikolaj Coster-Waldau) kill the only person Boutellis (Bogdan Dumitrescu) who can open the safe, Modesty arranges for Raphael to arrive who has the password for the computer that holds the details of the entry to the vault. The vault combination changes every 24 hrs and only the computer has the details. Modesty tells Miklos that the vault is booby trapped and it will kill everyone if Miklos tries to blow it open. Modesty calls Raphael, who figures that Henri is dead, and that Modesty & the rest of her crew is in a hostage situation.

As the criminals and their captives await Rapahel, Modesty takes on the leader of the criminals at the game of roulette. Modesty provokes Miklos by asking him to bet with real money. She says that every man who walks into the casino bets his life, his business, his love and it says a lot about who they are. She insinuates that Miklos is a coward. Miklos argues that all the money in the casino already belongs to him. They agree that if she wins twice in a row, a captive sworn to not tell what happened is released; when she loses, she has to tell the truth about her background to Miklos who has become fascinated by her. She relates her life story little by little in the manner of Scheherazade.

Modesty tells her life story in flashback beginning as an orphaned child in a refugee camp in the Balkans, to her meeting her mentor Professor Lob (Fred Pearson) (whom she saves from a gang of bullies who were trying to steal his briefcase from him). Lob and Modesty escape the refugee camp and together hike their way into Turkey. Lob teaches her his knowledge of various languages and martial arts until his death in Algeria (where the government forces were battling a group of rebels and Modesty+Lob were caught in the crossfire) where she makes her way to Tangier. Henri watches Modesty pick pocketing wallets from tourists and decides to give her a job at the casino. The time setting of the film is kept vague. Although flashback sequences involving warfare invoke World War II or other conflicts in the late 1940s and early 1950s (in keeping with the original comic strip), Modesty as an adult is shown using computers and other current (for 2004) technology.

In between Modesty keeps winning and provokes Miklos into honoring his bet and releasing the hostages every-time she wins twice in a row. She gets Olivette (Laura Iordache) (another waitress) free along with another prisoner who has been shot in the leg. Miklos also reveals that Henri sold his dad defective guns, due to which he died. Another waitress Danielle (Ana Maria Florescu) decides to escape while Modesty had kept Miklos and his crew engaged. But Miklos finds her missing and launches a search. She is shot and captured. As Raphael is delayed, Miklos decides to shoot Irina, but Modesty says she knows the combination and can get Miklos into the vault.

Modesty opens the safe, but unknown to Miklos, Rapahel was waiting at the other end, having entered the safe via a tunnel. The criminals eventually enter the safe but are confronted with a revenging Modesty. Rapahel takes on Miklos's men, while Modesty attacks Miklos and kills him. Modesty takes over the casino and cancels the drug deal that Henri was doing. She tells Raphael that the casino will no longer deal in drugs.