Motifs in the James Bond film series the degree to which Bond girls are pivotal to propelling the plot forward varies from one film to the next. Five of the Bond girls are "bad" girls (or at least working for the villain) who turn "good" (or switch sides) usually due to Bond's influence. Bond has fallen in love with only Tracy di Vicenzo in "On Her Majesty's Secret Service" and Vesper Lynd in "Casino Royale", but both of them die at or near the end of the respective films. Roald Dahl, a screenwriter of "You Only Live Twice", said he was given a formula to work to
Vesper Lynd mobile phone afterwards, he finds that she has left Mr. White's phone number; this enables Bond to track down and confront him at the movie's end. At the end of the 2008 film "Quantum of Solace", Yusef is revealed to be an agent working for Quantum, asked to seduce high-ranking women in the world's intelligence agencies. He is then "kidnapped" by Quantum, and the women are forced to become double agents in the hope of securing his freedom. This information vindicates Vesper in Bond's eyes, making him finally see that her "betrayal" was not her fault. He does not kill