Michael McMillian as PFC David 'Napoleon' Napoli
Jessica Stroup as PFC Amber 'Barbie' Johnson
Jacob Vargas as PFC Carlos 'Crank' Medina
Daniella Alonso as PFC Marisol 'Missy' Martinez
Flex Alexander as SGT Jeff 'Sarge' Millstone
Lee Thompson Young as PFC Delmar 'Del' Reed
Eric Edelstein as CPL Gilbert 'Spitter' Cole
Reshad Strik as PFC Michael 'Mickey' Elrod
Ben Crowley as PFC Scott 'Stump' Locke
Michael Bailey Smith as Papa Hades
Derek Mears as Chameleon
David Reynolds as Hansel
Jeff Kober as Colonel Lincoln Redding
Jay Acovone as Dr. Wilson
Philip Pavel as Dr. Paul Foster
Archie Kao as Dr. Han
Jason Oettle as Letch
Gáspár Szabó as Sniffer
Tyrell Kemlo as Stabber
Cécile Breccia as Pregnant Woman
Fatiha Quatili as Afghan Woman
Joseph Beddelem as Insurgent
Jeremy Goei as Clyde Martinez
A captive woman, forced to breed mutant children, is unable to supply healthy offspring after giving birth to a stillborn and is killed by Papa Hades, leader of the inbred mutant clan living at a nuclear testing village in New Mexico desert, designated as Sector 16. Following the events of the primary film, the us Department of Defense sent a military army to occupy the location and exterminate the remainder of the mutant clan. Colonel Lincoln Redding and a trio of scientists who are working therein area on installing a surveillance system are attacked by the mutants.
Later, a gaggle of National Guardsmen in training led by Sergeant Jeffrey "Sarge" Millstone are sent into the desert to resupply the scientists. They arrive to seek out the base camp abandoned after the mutants' attack. When the soldiers devour a faint distress call, Sarge organizes an enquiry and rescue mission through the hills. Napoleon and Amber, who stay behind at the camp, find and retrieve one among the missing scientists out of the camp's portable toilet, but he dies before he can warn them. the 2 are then attacked by the mutants, who destroy their transport and steal their weapons, forcing them to run into the hills to warn the others. The party is attacked by the mutants; Mickey is pulled into a bolt-hole and killed by Stabber, and Sarge is accidentally shot dead by Spitter's fratricide just before Napoleon and Amber reunite with the group. Spitter is killed after one among the mutants sabotages his rappelling gear as the others try to lower him down the hill. With their remaining gear stolen, they're forced to try to find another way to escape.
The remaining troops soon locate Redding, mortally wounded and unhinged from the mutant's attack. He warns them of the mutants' plans to capture women for breeding and divulges an exit route through the mining caves before committing suicide. After the group kills Stabber, Missy is captured and brought into the mining caves by Chameleon, forcing the opposite troops to rescue her. Stump leaves the group to flee on his own before being pursued and killed by Letch while attempting to climb down the hill. Separating from Crank and Delmar, Napoleon and Amber cross paths with Chameleon, whom they manage to kill. While escaping Sniffer, they're rescued by a nonviolent mutant named Hansel; Sniffer encounters Crank and Delmar, shoots the latter with one among the group's M4's and is killed by Crank in retaliation. While Hansel leads them to the exit, Delmar dies from his wounds after arriving at the mines' doorway. Napoleon joins Amber to save lots of Missy. Crank, who is attempting to unlock the blast door, dies when accidentally triggering an explosion of a crate of dynamites that he attempts to require with him.
After killing Letch, Napoleon and Amber locate Missy who was being savagely raped by Papa Hades. After distracting him, they manage to free her, but Hades soon returns and attacks them, triggering a vicious fight until the trio finally subdues and kills the mutant leader with a bayonet. because the survivors prepare to depart the mines, they're watched by an unknown mutant using their surveillance equipment.
Aaron Stanford as Doug Bukowski
Kathleen Quinlan as Ethel Carter
Vinessa Shaw as Lynn Carter-Bukowski
Emilie de Ravin as Brenda Carter
Dan Byrd as Bobby Carter
Tom Bower as Gas Station Attendant
Billy Drago as Papa Jupiter
Robert Joy as Lizard
Ted Levine as Big Bob Carter
Desmond Askew as Big Brain
Ezra Buzzington as Goggle
Michael Bailey Smith as Pluto
Laura Ortiz as Ruby
Maisie Camilleri Preziosi as Catherine Bukowski
Gregory Nicotero as Cyst
Retired detective Bob Carter and his wife Ethel are travelling from Cleveland to San Diego through the New Mexico desert for their silver wedding anniversary; with them are their three children, Lynn, Brenda, and Bobby, Lynn's husband Doug and their baby daughter Catherine, and their two German Shepherds, Beauty and Beast. They stop at a gasoline station where the elderly attendant suggests a different route through the hills, claiming it'll save them a few hours. shortly after, their tires are punctured by a hidden spike strip, causing the truck and trailer to crash.
Bobby is found by Brenda, but he decides to not tell his family about Beauty. Doug returns after heading towards the interstate and finding nothing but an enormous crater filled with numerous cars and other belongings. Worried that his father has not come , Bobby tells Doug and Lynn he doesn't think they're alone within the desert, even as Pluto and Lizard infiltrate the trailer. They attack and rape Brenda, who has stayed within the trailer with Catherine, while employing a distraction of immolating Bob to a tree to divert the others. When Lynn and Ethel return to the trailer, Lizard shoots both of them before abducting Catherine, then escapes with Pluto. Doug and Bobby return to get the carnage; Lynn and Ethel die shortly afterwards.
The next morning, Doug, together with Beast, began to rescue Catherine. He comes across an abandoned nuclear testing village through the miner town's cave system but is knocked unconscious by Big Mama. Awakening in an ice box, he escapes and encounters Big Brain who reveals the mutants' origins to him. Pluto appears and attacks Doug but he manages to realize the upper hand and kills Pluto with his own axe before killing another mutant, Cyst. After ordering Lizard to kill Catherine, Big Brain is mauled to death by Beast. Ruby manages to require the baby from Lizard and escapes through the hills.
Back at the trailer, Brenda and Bobby build an explosive trap, which they depart when Brenda is attacked by Jupiter. Meanwhile, Doug catches up with Ruby but Lizard attacks them before Ruby can hand Catherine over. A struggle ensues and Doug manages to defeat him with Cyst's shotgun. Ruby then gives Doug his daughter back. Lizard, still alive, aims the shotgun at Doug but Ruby tackles Lizard off a cliff, sending them both falling to their deaths.
Bobby and Brenda find Jupiter wounded from their trap and Brenda finishes him off with a pickaxe before the siblings are reunited with Doug, Catherine, and Beast. because the survivors of the Carter family embrace, an unknown mutant watches them from afar through binoculars.