NOTE: This spoiler was sent in by N.D.The movie starts off with a woman in labour, she's being observed by Papa Hades (Michael Bailey Smith...who played Pluto in the original), Hades gets tired of waiting for the baby to come out, so pulls out the child himself then after caressing the child's face beats the new born's mother to death with a rock.
Cut to a group of scientists getting stalked and slashed by the unseen mutants, whilst exploring the mining community. The last of which encounters a more compassionate mutant (much like the late Ruby was), Hansel (David Reynolds) who warns him just too late to flee, before another mutant Stabber (Tyrell Kemlo) slams a pickaxe into the unfortunate scientists skull. This just leaves the military personnel, Col. Lincoln Redding (Jeff Kober) to fire on them before pulls getting speared through the back as he looks over a cliff drop.
Next we cut to a training exercise by National Guards, which fails dismally, leaving the instructor, Sgt. Jeffrey "Sarge" Millstone (Flex Alexander) seriously p**ed at his troops, in particular the less gunho of the group, PFC David "Napoleon" Napoli (Michael McMillian). On their way home they drop by the area where the scientists had just been and go looking for the group, starting up a rescue mission after they hear groans on their walkie-talkies and then notice a mirror reflection being used as a spotting beacon.
They soon become stranded when their transport trucks go up in flames. Napoleon finds one of the scientists who's been stuffed down the porta-potty, he's dying of serve infections after being cut all over in several places and then immersed in sewage.
PFC Amber Johnson (Jessica Stroup) is then attacked by Stabber (one of the mutants we see at the beginning), he is then shot by PFC Mickey Elrod (Reshad Strik), but the bullet doesn't stop Stabber who only flees. Moments later, He seizes Mickey and proceeds to drag him through a hole into a cliff face; slowly bending one of Mickey’s legs the wrong way in the process (with our mutants have just claimed the first of the group). Another PFC, Cpl."Splitter" Cole (Eric Edelstein) is struck with an axe, while Sarge is accidentally shot dead by one of the group (due to the mutants hurling rocks at some of the more jittery of the group). The squad then lose Cole after the mutants cut the rope he's using to scale down the cliffs (he meets a messy end on the jagged rocks below).
Survivors; PFC Delmar Reed(Lee Thompson Young), PFC "Crank" Medina (Jacob Vargas), PFC "Missy" Martinez (Daniella Alonso), PFC "Stump" Locke (Ben Crowley), Amber and Napoleon then meet an injured & disfigured Redding who comes somewhat clean on what the group are dealing with. When asked how they got off the mountainside they're now stuck on, he states there is one way and blows his brains out before falling down the mountainside. Amber and Missy draw out one of the mutants (who attacked Amber earlier on) which turns out to be Stabber and lead him into an ambush where Stump, Delmar Reed and highly-strung Crank shoot him dead.
Missy is captured by Chameleon (Derek Mears) as she squats to (well you know) and the group following her abductors down a nearly vertical metal tube, all except Stump who decides to climb down the steep and jagged cliffs, without the safety ropes, as he passes a cave opening, agile mutant, Letch (Jason Oettle) suddenly slices off his arm, then uses his severed limb to wave at him as plummets to his messy demise far below.
Chameleon meanwhile is trying to get his 'freak on' with Missy, during which he 'French' kisses her, only to have his 'Gene Simmons' long tongue shorted by her biting a piece off. Papa Hades shows up removes Chameleon and starts violating Missy. Chameleon complaining over his deprived chance to have sex and his injuries, then encounters Amber & Napoleon who flush him out by firing at the walls striking and enraged Chameleon. He goes for them but Napoleon is now out of bullets so is sent flying back into a wall. Amber responds by gouging out Chameleon's right eye whilst Napoleon having now lost his temper, slams a rock over his skull. He continues to batter Chameleon even when our said mutant lies helpless on the floor...until his skull is completely pulverized, with his head now resembling a deflated football.
Delmar & Crank come across Chameleon as does Sniffer/Grabber (Gáspár Szabó); a near-sighted mutant (wearing glasses), who's been using his sense of smell to locate them and Chameleon. On coming across a now mutilated Chameleon, our specs wearing Sniffer/Grabber opens fire on them both with one of the groups own stolen machine guns, hitting Delmar who along with Crank return fire and send Sniffer/Grabber slumping over dead. Crank examines Delmar who claims it’s only a flesh wound and they must carry on the rescue.
They meet up with Amber & Napoleon who then encounter Hansel who is willing to lead them to where Missy is being held captive. Suddenly Delmar collapses bleeding continuously; it seems he was struck by more than one bullet this one being far more severe. Begging Crank not to freak out he departs from this life.
Crank has it out at Hansel then stomps off to come across a mass of dynamite boxes. He sees a chance to set up a death trap for the mutants…but sadly they’ve beat him too it, since as he picks up one container he sees far too late that it's been rigged to a cable and activator, with the latter striking the ground setting off an explosion which leads to Crank’s fiery end.
Our surviving duo (Amber & Napoleon) finally stumble across Missy, but also Letch who socks Missy and chucks Napoleon aside before going for Amber. But Napoleon is none too pleased by being hurled about so severs Letch’s Achilles tendon with a knife slash before jabbing the blade deep into his neck. Then just to be sure Amber skewers him on a bayonet.
This now just leaves Papa Hades, who makes his presence known by bursting straight through a wooden wall, before using Missy like a rag doll. Amber uses her last bullet to blow a hole in Hades’ skull, but this only makes him mad and he begins throttling her. Napoleon shoves a spear into Hades (which makes no difference whatsoever), nearly catching Amber who is not keen on being choked so pushes one her fingers down into his brain through the bullet hole in his head. This seems to give him the message that he’s now dead…and should thus fall over. On seeing this Missy gives him a multiple hefty kicks to his head (over raping her earlier) but this only makes him suddenly come round to seize her foot and go for a knife. He doesn’t get the chance to use it as he’s arm’s impaled preventing his reach, so Missy can painfully pound his manhood with a mallet before Napoleon gives Hades a sore throat to remember by shoving a bayonet down straight into the head mutant’s mouth…Hades is now no more…with no chance for a comeback.
As our surviving three stumble off out of the mines into the outside desert, we cut to a thermo imaging screen on a laptop as shown in the beginning of the movie…suddenly a partially gloved misshapen hand slams it down in anger…the limb belongs to mutant who is so not happy that there are survivors.