Deep in an underground laboratory, engineers Gary Sitterson (Richard Jenkins) and Steve Hadley (Bradley Whitford) discuss the recent failure in Stockholm and the plans for the next ritual. Meanwhile, American college students Dana Polk (Kristen Connolly), Jules Loudon (Anna Hutchison), Curt Vaughan (Chris Hemsworth), Holden McCrae (Jesse Williams), and Marty Mikalski (Fran Kranz) are planning to spend their weekend at Curt’s cabin in the forest. They are the Virgin, the Whore, the Athlete, the Scholar, and the Fool—in other words, the usual horror-movie cast.
From their lab, Sitterson and Hadley have remote control over the cabin and manipulate the students with mind-altering drugs. The lab technicians take bets on which kind of monsters will attack the students and discuss some recent failures of the ritual. In the cellar of the cabin—don’t go down there!—they find the diary of Patience Buckner, a victim of sadistic abuse from her inbred family in the cabin. Dana recites incantations from the diary and accidentally summons the zombies of the Buckner family.
Pheromones are released and Curt and Jules have sex in the woods. The zombies decapitate Jules and Curt escapes. Marty discovers surveillance equipment in his room but is dragged off by a zombie. The lab workers learn that the rite in Japan has failed and the American rite is humanity’s last hope. Curt, Holden, and Dana attempt to escape in their RV, but a tunnel collapse blocks their passage. Curt tries to jump the ravine on his motorcycle, but crashes into a force field and is killed. Holden and Dana realize that they are the victims of an experiment of some kind. They try to escape in the RV again, but Holden is killed by a zombie and Dana is attacked when the RV crashes into the lake.
The lab employees, seeing that Dana (the Virgin) is the last survivor, celebrate the success of the rite, but receive a call from the Director that Marty is still alive, as he escaped from the zombies. So, a virgin will be the last to die as desired, but which one? Marty saves Dana and takes her to a hidden elevator he found. They descend into the lab and find hundreds of glass cages holding all kinds of monsters. Dana realizes that any object found in the cellar would release a particular monster. They are cornered by security personnel, but they contrive to release all the monsters, which slaughter the guards and the laboratory staff in an orgy of bloodletting. Hadley is killed by a Merman and Dana stabs Sitterson to death.
Dana and Marty discover an ancient temple, where they are confronted by the Director (Sigourney Weaver). She explains that worldwide rituals appease the Ancient Ones, a race of cruel subterranean deities. Every region on Earth has a different ritual, but the American one involves the sacrificing of five slasher-film archetypes. They may die in any order, except that the Whore dies first and the Virgin last. The Director urges Dana to kill Marty and complete the ritual. Other rituals have failed and this one must save Humanity. Dana is about to do so, but is attacked by a werewolf, and Patience Buckner shows up and kills the Director. Dana apologizes to Marty for trying to kill him and decides that Humanity is not worth saving, and then they share a joint while waiting for the end. The temple collapses and the giant hand of Kronos rises from the Earth to begin the end of the world.
The film was directed by Drew Goddard (his first), written by Goddard, who had written Cloverfield, and Joss Whedon, and it was produced by Whedon. His dark humor is evident throughout. The writing team, who had worked together on Buffy the Vampire Slayer and Angel, wrote the screenplay in three days. Special effects were done by AFX Studio, and it was filmed in British Columbia. The writers loved the ensemble of characters in horror movies, which had lately devolved into idiots as horror movies became torture porn. A thousand actors were turned into one of sixty types of monsters in the film. As usual with Whedon, there were all kinds of studio problems and two years of delays—MGM actually went bankrupt—but the film received excellent reviews. It was distributed by Lionsgate in the end, which had produced most of the films Whedon was satirizing. It received 97% on Rotten Tomatoes.
Marty had to wear baggy clothes because he was the Fool and in fact was as well built as Hemsworth. Drew Goddard’s inspiration was his own childhood in Los Alamos, where he was surrounded by scientists calmly creating nuclear weapons. The Kyoto Ritual seems to refer to the movie The Ring, the Buenos Aires Ritual to King Kong, Stockholm to The Thing, and Madrid to Dracula. By the time the film was finally released, Hemsworth was world-famous as Thor. Contributing to the plot are The Evil Dead, 1984, Resident Evil, Friday the 13th, Cabin Fever, and Saw. The opening scene was an attempt to make the audience think they had walked into the wrong movie. Among the monsters were a giant tarantula, a giant frog, a giant snake, a giant centipede, a giant kitten, a killer robot, the Hellmouth Spawn from Buffy, a One-eyed, One-horned Flying Purple People Eater, and the KKK.