She poses as a radio seller working with René Mathis and later as Bond's companion in order to infiltrate the casino at Royale-les-Eaux, in which Le Chiffre frequently gambles.
Vesper is an agent of MI6's Station S, loaned to James Bond, much to his irritation, to assist him in his mission to bankrupt Le Chiffre, the paymaster of a SMERSH-controlled trade union.