The 1st part of the pre-title teaser shows a space shuttle (called a "Moonraker") being carried on a large cargo plane. Inside the shuttle, two men emerge from hidden compartments and start launch procedures for the shuttle. They fly off, destroying the cargo plane they were being ferried on. The shuttle was built for the British government and was en route there when it was stolen. M, head of MI6, orders Miss Moneypenny to contact his best agent, James Bond, and have him report in. Moneypenny says that Bond is currently in flight, returning from a mission in Africa. On board the private jet, Bond is betrayed by the flight attendant and the plane's captain, who both escape wearing parachutes. As Bond watches them escape, he is pushed out of the plan by Jaws (who returns from The Spy Who Loved Me). Bond plummets and is able to catch the pilot and wrestles the man's chute from him. As he puts it on and free-falls, he is attacked by Jaws. Bond pulls the chord on his own chute; Jaws tries the same but his chute doesn't open. He is seen falling into a circus tent; the first animated image of the opening title sequence suggests he fell into the high-wire safety net inside.
Bond reports to M's office where Q and Minister of Defense Gray are waiting. They report that the shuttle went missing somewhere over the Yukon Territory in Western Canada and, while the plane wreckage has been found, there's no sign of the Moonraker. Bond is ordered to begin his investigation of the shuttle's disappearance at the industrial complex where it was built by the Drax Corporation. Before he leaves, Bond is given a new wristwatch by Q that can fire specialized darts - one type are steel-tipped and armor piercing, the others contain cyanide.
Bond arrives at the Drax complex in California. He is taken by Corinne Dufour to industrialist and billionaire, Hugo Drax, for a brief meeting. Drax thanks Bond for appearing in person to apologize for the loss of his shuttle. Bond, however, is not there to apologize and, though he asks about the mysterious disappearance of the shuttle, he receives no conclusive answers. Bond is taken to meet Dr Holly Goodhead, who gives him a tour of the facilities. She suggests that Bond try out the g-force training vehicle. While he rides in it, Drax' personal bodyguard, Chang, refits the control panel (disabling the kill switch for the vehicle) and attempts to kill Bond with a fatal amount of g-force. Bond disables the machine by shooting one of the darts given to him by Q into the control panel. While Goodhead apologizes, Bond sees Chang leaving the control room.
Later that evening, Bond meets Miss Dufour and they have sex. He sneaks out of her room and into Drax' private office. Dufour discovers him there but does not attempt to stop him. Bond finds Drax' safe and photographs engineering schematics for a small electronic device and a larger pod of some sort both made by a glass company called Venini, located in Venice, Italy. As he and Dufour slip out of the office, they don't notice that Chang sees them go. The next morning, before he's scheduled to leave, Bond is asked to join Drax for pheasant hunting. During the match, Bond slyly kills an assassin planted nearby by Drax. He leaves just as Dufour arrives. Knowing of her betrayal, Drax tells her that she's fired; he lets his trained Beaucerons loose and they chase her through the forest, killing her.
Bond arrives in Venice, going immediately to the Venini glass works indicated in the plans he stole. He finds several workers making small containers that match the dimensions of those in the schematics. Joining a tour of the factory, he sees Holly Goodhead, who quickly leaves. Bond catches up with her and asks to meet her later, which she refuses. Bond heads off in a gondola - while floating down a canal, he is attacked by a knife-throwing assassin in a coffin, who kills Bond's pilot. Bond is able to kill him and activates the gondola's power motor and takes off. He is chased by two more men in a powerboat but eludes them by entering Venice's Grand Canal and activating the gondola's hovercraft which he rides into St. Mark's Square.
Bond returns that night to Venini & finds a laboratory where two scientists are working in a private lab. He notices a pod that matches the schematics from Drax' safe that contains some of the small glass containers he'd seen earlier. In the small containers are small electronic devices that contain vials of a clear fluid. Hearing the scientists returning, he hides, leaving one of the devices with the vials where it falls to the floor and shatters when the men move the pod. The liquid quickly becomes aerosol and the room is automatically sealed. Both men die but the animals in cages in the room do not. As he leaves, Bond is attacked by a man wearing Japanese kendo gear, who is soon revealed to be Chang. The two carry their combat into the Venini glassware museum and destroy it. They fight further, ending up behind a glass clock overlooking a fine restaurant. As they continue the fight, Bond notices crates that are bound for Rio de Janeiro that contain the large pods he'd seen in the lab. Eventually, Bond throws Chang through the clock headfirst into a grand piano, killing him.
Bond arrives later at Goodhead's hotel and finds her in her room. He reveals his knowledge of her being a CIA agent. The two spend the night together after Bond finds an airline ticket in her name to Rio de Janeiro. Bond leaves early in the morning and escorts M and Minister Gray to the Drax laboratory he'd found the night before. When they enter, the lab has been cleared out and all traces of the pods, vials and other experimental equipment are gone; only Drax remains in a lavishly decorated office. Gray apologizes for the intrusion and, after leaving the office, orders M to take Bond off the case. Bond gives M the vial he'd kept from the previous night and tells M to have it tested by Q with "extreme caution" due to is deadly nature. M tells Bond to take two weeks leave and asks where he'll go; Bond says he'll go to Rio de Janeiro to follow Goodhead and the Venini pods.
Bond arrives in Rio and begins to investigate again. He and his assistant, Manuela, find another storage facility owned by Drax, where Bond finds a shipping label from Drax Airfreight. In the street, Manuela is approached by a carnivale-goer in a large costume; it is Jaws, a hulking henchman with steel teeth hired by Drax soon after Chang was killed. Jaws attacks her but is prevented from killing her by some passing carnivale celebrators. Bond arrives, though he is unable to fend off Jaws completely, but the henchman is whisked away by another passing group of celebrators.
The next day, Bond takes a cable car to a observation platform overlooking Rio. He sees that planes belonging to Drax Airfreight are taking off from a nearby small airport. On the mountain, he once again finds Holly Goodhead, who tells him that the Drax planes have been departing frequently, every two hours. They both decide to return to Rio to investigate further, however, their cable car descent is interrupted by Jaws who bites through the heavy cable with his steel teeth. Bond and Goodhead battle the thug and are able to escape when Bond loops a chain around a cable and they slide down. Jaws follows in one of the cars but is unable to stop, colliding with the station at the bottom. As he tries to remove a wheel from his neck, he meets a young blond woman with large glasses, Dolly, who helps him and the two fall instantly in love.
Bond and Goodhead, having leaped from the chain before reaching the cable house, are picked up by an ambulance. The paramedics are likely Drax' men and the two are bound to their gurneys. Bond escapes his and is thrown from the ambulance, but Goodhead is unable to escape.
Bond reports to the new headquarters M and Q have set up outside Rio; Q reports that his analysis of the fluid in the vial reveals that it came from a rare orchid from the Amazonian Jungle region. The fluid, which originally caused sterility in the native tribe that inhabited the area, has been modified to cause death in humans only. Bond travels in a highly specialized boat to the Amazon and is engaged once again by Jaws and several henchmen in boats. Bond uses the defenses of his own boat to destroy most of them and escapes over a large grouping of waterfalls (they are actually the Iguazu Falls, hundreds of miles away near Argentina) by using a hang glider. Jaws winds up going over the falls in his boat. Bond crash-lands in the jungle where he spies a beautiful woman and follows her to a lagoon; he is cast into a pool where a large python is sent to kill him. Bond kills the snake with Goodhead's poison-tipped pen and is grabbed by Jaws. He is taken to Drax' control room where the launching of several Moonraker shuttles is being observed. Drax reveals that he'd originally ordered the theft of the British Moonraker because one of the original fleet developed a malfunction. Drax orders Bond to be taken to a conference room directly below the launchpad of one of the shuttles where Goodhead is trapped. Drax leaves them there to be incinerated during the launch. They escape the room and assume the identities of two Moonraker crew members after rendering them unconscious. They board the last Moonraker and are launched into space on a programmed flight plan. Bond checks the cargo area and sees several young couples as passengers.
In space, the Moonrakers arrive at a hidden space station. The station is activated and Drax initiates his ultimate plan: he will launch the orchid's fluids into the atmosphere of Earth where they will exterminate human life, leaving vegetation and animal life behind. The couples that he has brought into space will breed and their descendants will return to Earth as a new race of humans to populate it. Bond and Goodhead find the station's radar jammer and deactivate it, making the station visible from Earth. The British government launches a shuttle with a strike team towards the station.
Bond and Goodhead are discovered by Jaws who takes them to Drax. Bond remarks aloud that the only humans who will be allowed to live are those like Drax' "perfect specimens", IE, those who are physically fit and genetically superior. Jaws suddenly realizes that Drax' plan will not include either himself, because of his abnormal size and his steel teeth and Dolly because of her imperfect vision. Jaws decides to join forces with Bond and attacks the guards. A fight breaks out as the British shuttle arrives. Drax still orders the launching of the deadly pods. He is found escaping by Bond who fires one of his cyanide darts at Drax; he pushes the villain into an airlock and blasts him into space to his death. Meanwhile, the strike team has taken out the station team and fly away before the station, suffering catastrophic damage, explodes. Goodhead and Bond escape in Drax' shuttle, which is armed with a high-powered laser and pursue the pods. Jaws and Dolly plummet back to Earth in portion of the station; inside, Jaws opens a bottle of champagne and says "Well, here's to us!", his only spoken words in the Bond series.
Bond and Goodhead race towards the pods, destroying them all with the shuttle's laser cannon. Bond is forced to destroy the last one without the weapon's computer targeting system, but succeeds. Back on Earth, M an Q try to locate Bond, who is orbiting the earth in the shuttle and enjoying a gravity-free romantic tryst with Goodhead.