A British and a Soviet ballistic-missile submarine mysteriously disappear, prompting the urgent summoning of James Bond—MI6 agent 007—to investigate this troubling incident. While on his way to the briefing, Bond finds himself ambushed by a group of Soviet agents in the picturesque landscape of Austria. During a thrilling downhill ski chase, he successfully dispatches one of the attackers, managing to evade capture by the remaining agents.
The investigation leads Bond to Egypt, where plans for a cutting-edge submarine tracking system are being offered. Here, Bond encounters Major Anya Amasova, a KGB agent known as Triple X, who raises the stakes as a rival for the crucial microfilm plans. Forced to cooperate, they traverse the Egyptian terrain together, coming face-to-face with the formidable assassin known as Jaws—a towering figure with deadly steel teeth. A temporary truce is brokered between their respective British and Soviet superiors, allowing them to join forces and uncover the connection between the missing subs and the enigmatic shipping magnate and scientist, Karl Stromberg.
The duo proceeds to travel by train to Stromberg's secretive base located in Sardinia. In a nail-biting moment, Bond saves Amasova once again from the clutches of Jaws, their previous animosity slowly transforming into mutual affection. Disguised as a marine biologist and his "wife," the two infiltrate Stromberg's base where they learn about a newly launched mysterious supertanker, Liparus, which had set sail nine months earlier without ever docking at any known port.
Their escape becomes a race against time as they are pursued by Stromberg’s henchmen, comprising Jaws, a motorcycle-mounted henchman with a rocket sidecar, and Naomi, Stromberg's assistant piloting an attack helicopter. With the ingenuity of Bond's car—a Lotus Esprit equipped by Q Branch—they plunge underwater to avoid capture. In the climactic showdown, Jaws survives a spectacular car crash, while Naomi meets her end when Bond decisively destroys her helicopter with a well-aimed sea-air missile.
As Bond and Amasova explore Stromberg's underwater hideout, the Atlantis base, they confirm the activation of the submarine tracking system. Tensions rise when Amasova learns that Bond was responsible for the death of her former lover, Sergei Barsov. Sworn to exact vengeance on Bond after their mission, she vows to kill him.
Their journey leads them to board the USS Wayne, an American submarine, to investigate the Liparus. However, they fall into Stromberg's trap as the tanker is revealed to be a floating dock housing the missing submarines. Stromberg eagerly prepares for a catastrophic nuclear launch aimed at obliterating Moscow and New York City, intending to survive in his Atlantis sanctuary and lead a new civilization beneath the waves.
While Stromberg departs for Atlantis with Amasova, Bond boldly escapes, freeing the sailors held captive from the British, Russian, and American submarines. A daring battle ensues against the crew of Liparus, culminating in Bond discovering that the launched submarines are moments away from firing their nuclear missiles. With quick thinking, he tricks the subs into firing upon each other, leading to their destruction and a dramatic end to Stromberg's operation.
After the chaos, while the Pentagon orders the destruction of Atlantis, Bond's priority shifts to rescuing Amasova. He confronts Stromberg, leading to a fierce showdown that ends with the villain's demise. However, Jaws reemerges, escaping from Bond’s grasp by defeating a tiger shark in a startling turn of events.
In a final act of survival, Bond and Amasova exit in an escape pod, witnessing Atlantis’ destruction by torpedoes. In a poignant moment, Amasova contemplates vengeance but ultimately chooses to spare Bond, opting instead for a passionate embrace. As the Royal Navy recovers their pod, the couple shares an intimate moment through the viewing window, leaving their superiors astonished by their unexpected romantic entanglement.
