The film is an anthology of various science fiction and fantasy stories adapted from Heavy Metal magazine and original stories in the same spirit. Like the magazine, the film features a great deal of graphic violence, sexuality, and nudity. Its production was expedited by having several animation houses working simultaneously on different segments.
A sequel titled Heavy Metal 2000 was released in 2000.
The title sequence story opens with a space shuttle orbiting the Earth. The bay doors open, releasing a Corvette. An astronaut seated in the car then begins descending through Earth's atmosphere, landing in a desert canyon.
In the framing story the astronaut, Grimaldi, arrives at home where he is greeted by his daughter. He says he has something to show her. When he opens his case, a green, crystalline sphere rises out and melts him. It introduces itself to the terrified girl as "the sum of all evils". Looking into the orb known as the Loc-Nar, the girl sees how it has influenced societies throughout time and space.
In a dystopian New York City in the year 2031, cynical taxicab driver Harry Canyon narrates his day in film noir-style, grumbling about his fares and occasional robbery attempts, which he thwarts with a disintegrator installed behind his seat. He stumbles into an incident where he rescues a girl from a gangster named Rudnick, who had murdered the girl's father. She tells him about her father's discovery: the Loc-Nar, an artifact over which people are killing each other. Harry takes the girl back to his apartment, where she climbs into his bed and has sex with him. The next day, one of his fares is Rudnick, who threatens Harry if he does not cooperate. The girl decides to sell the Loc-Nar to Rudnick and split the proceeds with Harry. At the exchange, Rudnick takes the Loc-Nar out of its case and is disintegrated. Meanwhile, the girl informs Harry that she's keeping the money for herself and pulls a gun on him. Harry is forced to use his disintegrator on her. He keeps the money and writes it up as a "two-day ride with one hell of a tip."
A nerdy teenager finds a "green meteorite" and puts it in his rock collection. During a lightning experiment, the orb hurls the boy into the world of Neverwhere, where he transforms into a naked, bald muscle man called Den, an acronym for his earth name, David Ellis Norman. He witnesses a strange ritual, rescuing a nubile young woman who was about to be sacrificed to Uhluhtc. Reaching safety, she introduces herself as Katherine Wells from the British colony of Gibraltar. While she demonstrates her gratitude with sexual favors, they are interrupted by the minions of Ard, an immortal man who wants to obtain the Loc-Nar for himself. He orders Den to get the Loc-Nar from the Queen, who performed the ritual. Den agrees and infiltrates the palace, but is promptly caught by the Queen, who offers leniency if he has sex with her. He complies distracting the Queen while the raiding party steals the Loc-Nar. Den escapes and races back to rescue Katherine from Ard. Recreating the lightning incident that drew him to Neverwhere, he is able to banish Ard and the Queen. Refusing the opportunity to take the Loc-Nar for himself, Den rides with Katherine into the sunset content to remain in Neverwhere.
On a space station, space captain Lincoln F. Sternn is on trial for numerous serious charges presented by the prosecutor. Pleading "not guilty" against the advice of his lawyer, Sternn explains that he expects to be acquitted because he bribed a witness Hanover Fiste. Fiste takes the stand, but his perjury is subverted when the Loc-Nar, now the size of a marble, causes him to blurt out the truth about Sternn's evil deeds. Fiste rants with such fury that he changes into a muscled giant and chases Sternn throughout the station, breaking through bulkheads and wreaking havoc. Eventually, he corners Sternn, receives his promised payoff, and promptly shrinks back to his gangly original form. Sternn opens a trapdoor under Fiste, ejecting him into space. The Loc-Nar enters Earth's atmosphere with Fiste's flaming hand still clinging to it.
Because of time constraints, a segment called "Neverwhere Land," which would have connected "Captain Sternn" to "B-17," was cut.
The story follows the influence of the Loc-Nar upon the evolution of a planet, from the Loc-Nar landing in a body of water, influencing the rise of the industrial age, and a world war. This original story was created by Cornelius Cole III.
The original rough animatics are set to a loop of the beginning of Pink Floyd's "Time". The 1996 VHS release included this segment at the beginning of the tape. On the DVD release, this segment is included as a bonus feature. In both released versions, the sequence is set to the music of "Passacaglia" (from Magnificat), composed and conducted by Krzysztof Penderecki.
A World War II B-17 bomber nicknamed the "Pacific Pearl" makes a difficult bombing run with heavy damage and casualties. As the bomber limps home, the co-pilot goes back to check on the crew. Finding nothing but dead bodies, he notices the Loc-Nar trailing the plane. Informing the pilot, he heads back to the cockpit, when the Loc-Nar rams itself into the plane and reanimates the dead crew members as zombies. The co-pilot is killed, while the pilot parachutes away in time. He lands on an island where he finds a graveyard of airplanes from various times, along with the wrecked airplanes' zombified airmen.
So Beautiful and So DangerousEdit
Dr. Anrak, a prominent scientist, arrives at the Pentagon for a meeting regarding mysterious mutations that are plaguing the US. At the meeting, the doctor tries to dismiss the occurrences, but when he sees the Loc-Nar in the locket of Gloria, a beautiful buxom stenographer, he behaves erratically and attempts to sexually assault her. A colossal starship drills through the roof and abducts the doctor and, by accident, Gloria. The ship's robot is irritated at Anrak, who is actually a malfunctioning android, but its mood changes when it sees Gloria. With the help of the ship's alien pilot and co-pilot, the robot convinces Gloria to stay on board and have "robot sex". Meanwhile, the pilots snort a massive amount of plutonian nyborg before flying home, zoning out on the cosmos. Too intoxicated to fly straight, they crash land unharmed in a huge space station.
The Loc-Nar, now the size of a giant meteor, crashes into a volcano, changing a tribe of human outcasts into mutated barbarians who ravage a peaceful city. The elders desperately try to summon the last of a warrior race, the Taarakians. Taarna, a strong, beautiful, Taarakian warrior maiden, arrives too late to stop the massacre and resolves to avenge the city. Her search leads to the barbarians' stronghold, where she is captured, tortured, and left for dead. With the help of her Taarakian mount, she escapes and confronts the barbarian leader. Though wounded, she defeats him. With Taarna readying her final attack on the Loc-Nar, it tells her not to sacrifice herself as she cannot destroy it. She does not relent, and her self-sacrifice destroys the Loc-Nar.
As the final story ends, the Loc-Nar terrorizing the girl is similarly destroyed, blowing the mansion to pieces. Taarna's reborn mount appears outside and the girl happily flies away on it. It is then revealed that Taarna's soul has been reincarnated in the girl. The girl's hair color changes to that of Taarna and she reveals a Taarakian mark on her neck.
- Percy Rodriguez (uncredited) as voice of the Loc-Nar
- Don Francks as Grimaldi
- Caroline Semple as Girl
- John Candy as Desk Sergeant
- Marilyn Lightstone as Whore
- Susan Roman as Girl, Satellite
- Richard Romanus as Harry Canyon
- Al Waxman as Rudnick
- Harvey Atkin as Alien, Henchman
- John Candy as Den
- Jackie Burroughs as Katherine Wells
- Martin Lavut as Ard
- Marilyn Lightstone as Queen
- August Schellenberg as Norl
- Rodger Bumpass as Hanover Fiste
- Joe Flaherty as Lawyer
- Eugene Levy as Captain Lincoln F. Sternn
- John Vernon as Prosecutor
- Douglas Kenney as Regolian
- Don Francks as Co-Pilot (Holden)
- Zal Yanovsky as Navigator
- George Touliatos as Pilot (Skip)
- Rodger Bumpass as Dr. Anrak
- John Candy as Robot
- Joe Flaherty as General
- Eugene Levy as Male Reporter / Edsel
- Alice Playten as Gloria
- Harold Ramis as Zeks
- Patty Dworkin as Woman Reporter
- Warren Munson as Senator
- Don Francks as Barbarian
- August Schellenberg as Taarak
- Zal Yanovsky as Barbarian
- George Touliatos as Barbarian
- Vlasta Vrána as Barbarian Leader
- Mavor Moore as Elder
- Thor Bishopric as Boy
- Len Doncheff as Barbarian
- Cedric Smith as Bartender
- Joseph Golland as Councilman
- Charles Joliffe as Councilman
- Ned Conlon as Councilman