In France, James Bond, looking for arch enemy Ernst Blofeld, saves a young woman from suicide. Immediately afterwards he is attacked by two thugs; while they struggle, the woman escapes. Bond discovers that the woman is the Contessa Teresa Di Vincenzo, known as Tracy. Bond bails her out when she gambles in the casino without sufficient funds and, after another mysterious thug has attacked him, she sleeps with him in order to fulfill what she sees as a business contract.
The next morning, Tracy leaves and two armed men accost Bond. He is taken to see Tracy's father Draco, head of Union Corse, the second biggest crime syndicate in the world. Draco thanks Bond for saving his daughter and asks him to marry her in order to give her the strict male attention that he feels she requires. Bond refuses, despite a promised dowry of a million pounds, but becomes more interested when Draco promises to tell his future son-in-law of the whereabouts of Blofeld.
In London, M, unhappy with Bond's progress, takes him off the Blofeld trail. Bond asks Miss Moneypenny to draft his resignation but she ensures that the memo merely asks for two weeks leave, for which both Bond and M thank her.
Bond returns to Draco and discovers that Blofeld is connected to a Swiss lawyer. However, Tracy, who insists that she will only marry a man whom she chooses, does not appreciate the marriage deal. However, an intimate relationship between Bond and Tracy soon develops.
In Switzerland, Bond breaks into the lawyer's office and copies secret documents relating to Blofeld. The master criminal has applied to the Royal College of Arms to have his claim to nobility recognised, believing that he is the Count De Bleuchamp - Bleuchamp being French for Blofeld. Bond meets Sir Hilary Bray, from the college, who has agreed to meet Blofeld to discuss the claim, and it is decided that he will adopt Sir Hilary's identity for the meeting.
Bond, in disguise, is met in Switzerland by Irma Bunt, Blofeld's secretary, and taken to the heavily guarded 'Bleuchamp Institute For Allergy Research' in the Swiss Alps. He is cordially received and given a luxurious, but locked, room. At dinner, Bond discovers that he is sharing the accomodation with 12 young women. Irma tests him on his knowledge of heraldry but Bond manages to satisfy her, while attracting the attention of the women, whom he soon begins seducing.
Taken to meet Blofeld, Bond discovers that he has had plastic surgery to remove his ear lobes - the characteristic of the Bleuchamps - and is shown around his laboratory. However, Blofeld discovers Bond's true identity and imprisons him after revealing his latest plot against the world. He intends to unleash a virus that will render sterile all plant and animal life in the world, unless he is given an international amnesty, has his title recognised and is allowed to retire into private life. The twelve girls are to be used as the agents for releasing the virus, after extensive hypnosis during their stay at the Institute.
Bond escapes and is chased on skis down the mountain by Blofeld and his soldiers. In the village, he unexpectedly meets Tracy, who drives him out of the village in her car, pursued by the enemy. After surviving the chase, which takes them into the middle of a stock car rally, the couple hides in a stable overnight. Next morning, however, they are found and chased again, and Tracy is captured.
Returning to London, Bond is angered to discover that the UN has decided to pay off Blofeld. He contacts Draco to organise an independent mission to stop Blofeld and rescue Tracy. Draco's helicopters penetrate Blofeld's defences, rescue Tracy and destroy the Institute. Bond pursues Blofeld on a bobsleigh and manages to overpower him, leaving his nemesis hanging from a tree.
Bond marries Tracy at a lavish ceremony and the couple embarks on their honeymoon. But their car is ambushed by Blofeld and Bunt. Attempting to shoot Bond, they hit Tracy and she dies in Bond's arms.
