While driving along a coast road in Portugal, Bond (George Lazenby) is passed by a woman who drives to a beach and tries to drown herself. As Bond saves her he is attacked but is able to beat them off in time to see the woman drive away.
At a casino later he sees the same woman gambling. Her name is Contessa Teresa di Vicenzo “Tracy” (Diana Rigg) and she invites Bond to her room in payment for him paying her tab. But again Bond is attacked and again defeats the man but on his return to his room finds Tracy who has stolen his gun. She threatens to kill Bond before he disarms her. She says she doesn’t know who the man was but the next morning when she leaves the hotel and Bond tries to follow her he is waylaid by more men and taken to Tracy’s father. He is Marc-Ange Draco (Gabriele Ferzetti), head of Union Course, a powerful crime organization, who offers Bond a substantial amount of money to marry Tracy as he is concerned about her state of mind. Bond turns down the offer but says he will continue to date her if Draco helps him track Ernst Stavro Blofeld (Telly Savalas), leader of SPECTRE.
On his return to London, M orders Bond to end his obsession with Blofeld but Bond in return hands in his resignation to Moneypenny (Lois Maxwell) who changes it to two weeks leave.
So Bond continues to go after Blofeld going to Portugal initially to a party organised for Draco. There Tracy insists her father helps Bond and suggests he tries Bern in Switzerland. Once there he sneaks into the offices of a Swiss lawyer called Gumbold and uncovers the fact that Blofeld is in contact by letter with the London College of Arms. Back in London he meets with a college expert who tells him of Blofeld’s claim to the title of Comte Balthazar de Bleuchamp of Switzerland.
Taking on the identity of Sir Hilary Bray, an Arms delegate, Bond returns to London to update M on his discovery. Given permission to continue his investigations he goes to Blofeld’s compound in the Swiss Alps. There he discovers Blofeld masquerading as an epidemiologist researching into allergies. Blofeld has a number of beautiful girls supposedly cured of allergies, two of which Bond seduces. He also discovers that while the girls are in bed they are hypnotised by strange lights and sounds. Later Bond eavesdrops on a meeting with the girls and discovers that Blofeld is giving them Christmas presents containing a communication device and a deadly virus. Blofeld will demand that the US give him a pardon and recognition as a count or he will instruct the girls to release the virus throughout the world.
When Bond tries to sneak into the room of one of the girls he seduced the next day, he comes face to face with Blofeld’s assistant, Irma Bunt. He is taken to Blofeld and, because of a rare slip up, he is identified as James Bond. He is imprisoned but manages to escape, steal some skiing gear and ski down the mountain chased by Blofeld’s henchmen. He collects Tracy and they make their escape in her car staying in a secluded barn overnight where Bond proposes to Tracy.
The next day they leave the barn on skis chased again by Blofeld and his men. However, to prevent them from escaping Blofeld causes an avalanche and they are caught. They dig Tracy out but leave Bond for dead. Bond though escapes and returns to London to plan Tracy’s rescue and to scupper Blofeld’s plan. M refuses to attack Blofeld’s compound so Bond goes to Draco for help.
Bond, along with Draco and his men attack the compound, rescue Tracy and stop Blofeld from giving the order to the girls. Tracy flies away with her father and Bond chases Blofeld who has escaped on bobsled. Bond’s bobsled catches up with Blofeld and after a brief fight Blofeld is injured and unconscious.
Bond and Tracy are married and leave the reception in Bond’s Aston-Martin. A little later they stop to remove some of the decorations from the car. At that moment a car roars past with Blofeld and Irma Bunt who fires at them with an assault rifle and Tracy is killed.