Alien 3 (stylized as Alien3) is a 1992 science-fiction horror film, and the debut feature of director David Fincher. This film is the third installment of the Alien franchise. Continuing after the events in Aliens (1986), an escape pod from the Colonial Marine spaceship Sulaco crash-lands on a prison-run refinery planet, killing everyone aboard except Lieutenant Ellen Ripley (Sigourney Weaver). Unknown to Ripley, an Alien organism was also aboard the escape pod, which then begins a killing spree in the prison.
The Colonial Marine spaceship Sulaco experiences an onboard fire and launches an escape pod containing Ellen Ripley (Sigourney Weaver) along with Newt, Hicks, and the damaged android Bishop. All four are in cryonic stasis. During the launch, the ship's medical scans of the crew's cryotubes show an Alien facehugger attached to one of the crewmembers. The pod then crashes on Fiorina 'Fury' 161, a foundry facility and penal colony inhabited by all-male inmates with "double-Y" chromosome patterns and histories of physical and sexual violence. After some inmates recover the pod and its passengers, an Alien facehugger is seen approaching the prison dog. Ripley is taken in and awakened by Clemens (Charles Dance), the prison doctor, and is told she is the only survivor of the crash. Many of the ex-inmates, led by Dillon (Charles S. Dutton), have embraced an apocalyptic, millenarian version of Christianity. Ripley is warned by the prison warden, Harold Andrews (Brian Glover), that her presence among them may have extremely disruptive effects.
Suspicious of what caused the escape pod to jettison and what killed her companions, Ripley requests that Clemens perform an autopsy on Newt. She fears that Newt may be carrying an Alien embryo in her body, though she does not share this information. Despite protests from the warden and his assistant, Aaron (Ralph Brown), the autopsy is conducted. No embryo is found in Newt's body, and Clemens proclaims she simply died in the crash. Meanwhile, Ripley's unusual behavior begins to frustrate the warden and is agitating the prisoners.
A funeral is performed for Newt and Hicks, during which their bodies are cremated in the facility's enormous furnace. In another section of the facility, the prison dog enters convulsions, and a seemingly full-grown Alien bursts from its body. The Alien soon begins to attack members of the colony, killing several and returning an outcast prisoner Golic (Paul McGann) to his former deranged state. To get answers, Ripley recovers and reactivates the damaged android Bishop, who confirms that there was an Alien on the Sulaco and it came with them to Fiorina in the escape pod. She then informs Andrews of her previous encounters with the Aliens and suggests everyone work together to hunt it down and kill it. Andrews does not believe her story and explains that the facility has no weapons. Their only hope of protection is the rescue ship being sent for Ripley by the Weyland-Yutani Corporation.
Back in the prison infirmary, while talking to Ripley about the situation, Clemens is killed by the Alien, but when it is about to attack Ripley, it suddenly pauses, then retreats, mysteriously sparing her life. She runs to the mess hall to warn the others, Andrews orders Aaron to take her back to the infirmary, but the alien suddenly ambushes and kills Andrews. Ripley rallies the inmates and proposes they pour highly flammable toxic waste, which is stored at the facility, into the ventilation system and ignite it to flush out the creature. An explosion is caused by the creature's premature intervention, resulting in several deaths. Using the medical equipment aboard the Sulaco escape pod, Ripley scans herself and discovers the embryo of an Alien Queen growing inside her. She also finds out that the Corporation truly wants the Queen embryo and the adult Alien, hoping to turn them into biological weapons. Deducing that the mature alien will not kill her because of the embryo she carries, Ripley begs Dillon to kill her; he agrees to do so only if she helps the inmates kill the adult creature first. They form a plan to lure it into the foundry's molding facility and drown it in molten lead by trapping it by closing a series of doors. The bait-and-chase style plan results in the death all the remaining prisoners, including Dillon, David, Gregor, and Kevin, except Morse (Danny Webb), who pours the lead. The Alien, covered in molten metal, escapes the mold and is killed by Ripley when she turns on fire sprinklers and sprays the beast with water, causing its exoskeleton to cool rapidly and shatter via thermal shock.
While Ripley battles the Alien, the Weyland-Yutani team arrives, including a man who looks identical to the Bishop android, claiming to be its creator. He tries to persuade Ripley to undergo surgery to remove the Queen embryo, which he claims will be destroyed. Ripley refuses and steps back onto a mobile platform, which Morse positions over the furnace. The company men shoot Morse in the leg, and Aaron picks up a large wrench and strikes Bishop II over the head with it. Aaron is shot dead, and Bishop II and his men show their true intentions, begging Ripley to let them have the "magnificent specimen". Ripley defies them by throwing herself into the gigantic furnace, just as the alien Queen begins to erupt from her chest. Ripley grabs the creature, holding on to it as she falls into the fire to her death.
The facility is closed down and the last surviving inmate, Morse, is led away. A sound recording of Ripley (her final lines from the original Alien) is heard from the Sulaco escape pod.
- Sigourney Weaver as Ellen Ripley, reprising her role from the previous two Alien films. Ripley crash-lands on Fiorina 161 and is once again burdened with the task of destroying another of the alien creatures.
- Charles S. Dutton as Dillon, one of Fiorina's inmates who functions as the spiritual and de facto leader amongst the prisoners and attempts to keep the peace in the facility.
- Charles Dance as Jonathan Clemens, a former inmate who now serves as the facility's doctor. He treats Ripley after her escape pod crashes at the start of the film and forms a special bond with her. Before he is killed, Clemens laments to Ripley why he was originally sent to Fiorina, describing it as "more than a little melodramatic." Fincher initially offered the role to Richard E. Grant, hoping to reunite him with Withnail and I co-stars Ralph Brown and Paul McGann.
- Brian Glover as Harold Andrews, the prison warden. He believes Ripley's presence will cause disruption amongst the inmates and attempts to control the rumors surrounding her and the creature. He rejects her claims about the existence of such a creature, only to be killed by it.
- Ralph Brown as Aaron, the assistant of Superintendent Andrews. The prisoners refer to him by the nickname "85", after his IQ score, which annoys him. He opposes Ripley's insistence that the prisoners must try to fight the alien, and repudiates her claim that Weyland-Yutani will collect the alien instead of them.
- Paul McGann as Golic. A mass-murderer and outcast amongst the prison population, Golic becomes very disturbed after being assaulted by the alien in the prison's underground network of tunnels, gradually becoming more and more obsessed with the alien. In the Assembly Cut of the film, his obsession with and defense of the creature lead to murder, and his actions jeopardize the entire plan.
- Danny Webb as Morse, an acerbic, self-centered, and cynical prisoner. Although he is wounded by a company guard, Morse is the only survivor of the entire incident.
- Lance Henriksen playing an unnamed character but credited as Bishop II, he appears in the film's final scenes, claiming to be the human designer of the Bishop android. He wants the alien Queen that is growing inside Ripley for use in Weyland-Yutani's bioweapons division. He also reprises the role of Bishop from the previous movie, albeit in animatronic form.
- Tom Woodruff, Jr. (uncredited) as the Alien. This Alien is different from the ones in previous installments due to its host being quadrupedal (a dog in the theatrical cut, an ox in the assembly cut). Initially a visual effects supervisor, Woodruff decided to take the role of the creature after his company, Amalgamated Dynamics, was hired by Fox. Woodruff said that, following Sigourney Weaver's advice, he approaches the role as an actor instead of a stuntman, trying to make his performance more than "just a guy in a suit." He considered the acting process "as much physical as it is mental."
- Pete Postlethwaite as David, an inmate smarter than most who is killed by the creature in the bait-and-chase sequence.
- Holt McCallany as Junior, the leader of the group of inmates who attempt to rape Ripley. He has a tattoo of a tear drop underneath his left eye. In the Assembly Cut, he sacrifices himself to trap the alien as redemption.
- Peter Guinness as Gregor, one of the inmates who attempts to rape Ripley, he is bitten in the neck and killed by the Alien during the bait-and-chase sequence.
Additional prisoners were played by Christopher Fairbank (as Murphy), Phil Davis (as Kevin), Vincenzo Nicoli (as Jude), Leon Herbert (as Boggs), Christopher John Fields (as Rains), Niall Buggy (as Eric), Carl Chase (as Frank), Clive Mantle (as William), and Deobia Oparei (as Arthur).