Underworld is a subterranean science fiction film that focuses on a post-apocalyptic underground city-state in constant subterranean warfare with an unseen other sister city-state. On the two-hundred and fiftieth anniversary of the Sealing rumors fly regarding a strange sound coming from the presumed desolate surface. An insurrectionist movement forms that seeks to discover the source and nature of the sound.
In the middle of the 22nd century, two major power blocs dominated the Earth but a war between the two completely devastated the surface plunging the world into an extinction level event. Prior to the end, a few corporations, private individuals and civilians worked together to construct a series of underground cities as a refuge from the coming disaster.
Two hundred and fifty years later, in the early 25th century, the Human Continuity Coalition operates as an impromptu government for the underground city-state. They urge citizens to maintain the rationing of water and food. While Hassan Decker, a worker in an area of the city-state known as The Foundry as part of the construction crew repairing the walls of the city-state, starts on a path of disillusionment. The last few months have seen an increase in attacks from another sister city-state, the Underdwellers refer to them derogatorily as "Groundhogs." Zeke, the mysterious leader of a movement called the "Insurrectionists," within the city-state seek to remove the HCC from power while preaching that the Church is a lie and plan to return everyone to the surface where life is better. Hassan and other citizens take vitamins to prevent hair loss and muscular deterioration.
Though the city-state goes out of its way to maximize civilian quality of life by legalizing many narcotics and pharmaceuticals for recreation. They have begun instituting a one-child policy as well as legalizing prostitution and polyandry in order to curtail the issues that come with a relatively low population of females and supporting a very liberal view of sexuality including nudity. The HCC goes through periods known as "Audits" which is a census that determines the amount of males, if the male population exceeds the amount of females by an extreme margin, males older than 40 are sent to "the Row" where they are never seen again but the Church states that they are reborn in the "Nursery," usually several months after the Audits. While an excess amount of males younger than 40 are drafted and placed on the front-lines in the Groundhog Wars.
When Hassan's son Nestor is drafted into the HCC's Molemen unit, he is sent onto the front-lines after testing proficiently to be a Gopher, a pilot for a one-man combat drill. Nestor's first experience with subterranean warfare leads him to suffer severe PTSD as the HCC calls on more and more attacks on the Groundhogs.
Nestor fights in a battle near a subterranean river and engages in hand to hand combat with a citizen of the Groundhogs who is revealed to be a woman named Sybil. His Gopher sends a distress call to the HCC, a rescue unit on its way. Nestor and Sybil become fast friends and exchange tales of their respective city-states and agree that both sides need to put an end to the hostilities and join together in peace. Sybil claims that her people have discovered a group of humans, she calls "Sky People." Nestor doesn't believe her at first but slowly turns to believe it when she shows him a holographic representation of her city-state and the arrival of the Sky People. When the rescue team arrives, Nestor and Sybil are stripped naked and taken to a Decontamination chamber. Sybil is taken away and Nestor is clothed and meets the government leadership and is hailed as a hero who is the first Gopher to capture a Groundhog prisoner. Hassan's childhood friend Soloman is forced on Nestor due to her age and lack of any husbands making her a piriyah among the citizens. Nestor and Soloman meet and discuss various subjects but find themselves very different people but the two are forced to have sex by government mandate. The two manage to find common ground when they lay in bed together.
Though a relatively young and largely untested hero, Nestor ascends to being the Gopher team's assistant company commander and grows increasingly more disillusioned by the HCC. He is scrambled for another battle with the Groundhogs and convinces his team to join him. They continue onto their neighboring city-state without firing a shot. Meanwhile, Hassan and Booker come together when an Audit is held and determines that a dozen men will have the 'honor' of going down the Row which includes Hassan's foreman Trevino, the oldest of the dozen men. Trevino and the other men are given a grand send-off and prayers are spoken as he is lead off down the Row. The disappearance of the Gopher team forces Captain Cantu to put a Hunter Squad on them, killing Erasmo and Lieutenant Odom but injuring Nestor. Major Turner states his clear opposition to Cantu who then murders Major Turner and assumes his place as Commandant of the Self-Defense Corps. Cantu publicly declares that Major Turner died in his sleep while the Gopher company, with the renowned hero Nestor as a member, were killed by Groundhogs and asks Premier Belkin for a decisive and final strike against the Groundhogs.
This announcement causes Hassan and Booker to join the Insurrectionists. They join a small group of friends at a secret meeting after curfew hours, stating that there is a mysterious sound that was heard by a group of Insurrectionists heading for the surface that remains unexplained as the group was apprehended by the SDC. Hassan and Booker volunteer to join a new group that will break the Seal and venture out onto the surface. Just then, the secret meeting broken up by the SDC and the group splits. Hassan and Booker both agree that they will meet the others in the morning to make for the surface. Soloman is revealed as snitching on them.
Nestor awakens in his Gopher as he is rescued by Groundhog emergency personnel. He is severely injured, but Groundhog medicine helps improve his condition immensely. When he comes to he talks with the Chief Executive of the Groundhog city-state, they claim that despite the decades-long conflict that both groups are merely human and that there is more important matters at stake for humanity's survival. The Chief Executive reluctantly asks that Nestor stay in the Infirmary as it is protocol due to his perceived danger. Nestor deduces that the Groundhog city-state is predominantly female due to an extreme lack of males.
Hassan and Booker arrive at the bottom of the Foundry where they meet a few others including Soloman and Zeke, who is revealed as being Captain Cantu. Cantu declares that she is on their side and wants the best for everyone. Cantu then reports to Premier Belkin notifying him that she intends to murder all of the Insurrectionists as a recent strike against them killed the original Zeke and likely the rest of the Insurrectionists. The group scales up an abandoned staircase which has become loose over the last two centuries, an earthquake causes two members to fall to their deaths. This also causes them to hear the strange noise.
Nestor wakes in the Infirmary and plots an escape. He succeeds and is completely caught off guard by what he sees. The group continues to scale up the staircase and reaches the Seal. Cantu then pulls a weapon and states that she has a High Yield Laser Weapon which can vaporize anyone or anything. She kills two more members of the group, leaving only Hassan, Booker and Soloman. Cantu reveals to Hassan and Booker that Soloman betrayed them by snitching on them. Hassan and Booker coordinate taking down Cantu, Soloman is injured while Hassan turns the gun on Cantu and vaporizes her. Hassan turns the gun toward Soloman who pleads for her life and reveals that she is pregnant with Nestor's child causing him to lower the weapon and fire at the Seal, opening it. They go through a long dark hallway and come to an entrance, where they begin hearing that strange noise getting louder. They find that the source of the noise is a speaker at the end of the hallway. He fires again at another seal causing a giant flood of light inside of the hallway. Hassan, Booker and Soloman struggle to readjust to the extreme brightness but eventually do. They see an immense blackened desert ahead of them and see their exit coming out of the base of a small hilltop. The trio walk around and find a lone booth in the middle of the desert near a degraded sign that states: BAKER 24/LAS VEGAS 116. They deduce that the sign rubbing against metal was the sound that the Insurrectionists heard. The trio slump down onto the desert floor and are depressed that it looks like the surface was always uninhabitable. They resolve to return to the city-state, defeated and unready to face the consequences of the murder of Cantu. Nearby, a solitary green flower dances in a light breeze.
As they approach the inside of the chamber, an aerial vehicle approaches them and descends. The trio is astonished at what they see. Nestor exits with the vehicle along with a squad of female commandos behind him. He reunites with them and states that they've been wrong about the Groundhogs and that they are experiencing similar issues that they are and that they are just people.
Back at the underdweller city-state, Premier Belkin plans to send a follow-up squad in search of Captain Cantu. An earthquake strikes to which Belkin exclaims,"another one?" But the earthquake doesn't subside, the Foundry Wall falls as a giant drill appears having broken through the barrier. Deputy Premier Kato then holds Belkin at gunpoint telling him to resign his position. Belkin obliges, before Kato reveals that he was in fact Zeke the whole time and that a beautiful new world awaits.
Several months later, Nestor and Soloman welcome their first born child, whose sex is not revealed. Hassan and Booker suggest they name the child after Trevino.
- Hassan Decker- Protagonist, Arabic-descent, works in the Foundry as part of a construction crew but grows increasingly more disillusioned by the heinous acts of the HCC and wary of the war with the Groundhogs. Mid-late 40s. A.
- Booker Arden- Loyal wife of Hassan, she works in an area of the city-state known as The Market, as part of a financial district and marketplace of trade, but as a Courtesan. She shares his disillusionment and supports him. Late 30s/early 40s. A.
- Nestor- The government mandated only child of Hassan and Booker, Nestor is a 18-year-old who is drafted into Commandant Turner's Molemen and due to high apitude becomes a Gopher pilot. A.
- Hinton- Best friend of Nestor, who is also drafted into the Moleman unit but is killed when he freaks out during a live fire excercise. 17-year-old. D.
- Erasmo- Wingman of Nestor within the Molemen Gopher company. 18-year-old. D.
- Trevino- Foreman of Hassan's construction crew and an elder who doubles his time in the Garden, where the city-state grows fruits and vegetables in hydroponic greenhouses and has a bookshelf of books that an ancestor saved that highlight the fiction of the 20th and 21st century. Mid 40s. D.
- Soloman- Best friend of Hassan, she has an affection for him but muzzles it around Booker. She remains loyal to the city-state government. Though many years his senior, she becomes sexually involved with Nestor and over time genuinely loves him. Mid/late 30s. A.
- Premier Belkin- Leader of the underdweller city-state, struggling to hold onto power. Late 30s. A.
- Deputy Premier Kato- Second-in-command, sees the weakness of Belkin and the insanity of Commandant Turner but is interested in imposing progressive ideals onto the city-state as to make it a utopia. Early 30s. A.
- Commandant Major Turner- Leader of the law enforcement/military wing of the Human Continuity Coalition known as the Self-Defense Corps, charged with carrying out summary executions, administering martial law and maintaining government stability. Turner has held the position for decades and despite his advanced age. 60s. D.
- Superintendent Captain Cantu- Administrator of the Self-Defense Corps Academy and technically the second-in-command of the HCC's SDC. Opportunistic and decisive, she is waiting until Turner dies to assume his position and remove the HCC civilian leadership as she sees them as impotent in their defense of the city-state and fending off the Insurrectionists. 40s. D.
- Company commander Lieutenant Tad Odom- Leader of a Gopher company constantly attacking the Groundhogs but is warn by the endless death of friends and subordinates. Early 30s. D.
- Zeke- Fabled leader of a group known as, "the Insurrectionists," which think it is time to return to the surface. R.
- Mendez- Minister of a city-state sponsored church that preaches reincarnation and prayer to a deity known as "Abraxas." 20s. U.
- Lieutenant Sybil- A female Gopher pilot for the Groundhogs, befriends Nestor before their rescue by the HCC. She is imprisoned and her memory wiped. 20s. U.