The film first entered development in 2005, when Screen Gems bought the spec script by Cory Goodman. In 2006 Andrew Douglas was attached to direct and Gerard Butler was attached to star. They were eventually replaced by Stewart and Bettany in 2009 and filming started in Los Angeles, California, later in the year. The film changed release dates numerous times throughout 2010 and 2011. It was especially pushed back from 2010 to 2011 to convert the film from 2D to 3D. It was released in the United States and Canada on May 13, 2011.
In the future, the war between humans and vampires has devastated the world. The Church, the future incarnation of the Christian faith, created an elite group, dubbed "priests", who were capable of fighting vampires. Most of the vampires were killed or put in reservations while the Church created isolated, heavily guarded cities where most of the remaining humans live. No longer needing the Priests, the Church disbanded the priests.
One day an unnamed priest, is approached by Hicks, the sheriff of a nearby town. Hicks tells him that his brother Owen, sister-in-law (and ex girlfriend, Shannon) were killed by vampires and his niece Lucy was kiddnaped. Hicks asks for his help tracking down Lucy and Priest goes against the wishes of Monsignor Orelas, the leader of the Church, to do so. Orelas then sends a group of four Priests to capture him and bring him back, dead or alive.
After saying goodbye to his dying brother, Priest and Hicks arrive at a vampire reservation, where they discover that the vampires have taken shelter in Mira Sola. Mira Sola is a vampire hive where Priest lost several of his priest comrades in a botched mission. There, they are joined by Priestess, one of the priests sent after Priest, who decides to help him because she is in love with him. The group discover that the vampires are using trains to travel, slowly amassing a new army and intending to attack the city Priest is from, killing the surviors and destroying the chuch. They also discover that the inhabitants of Mira Sola had tunneled to the city of Jericho, where the other three priests went.
Once in Jericho, the other three priests are soon confronted by Black Hat, who asks them to join him and the vampires, but kills them when they refuse. Black Hat and his army of vampires slay the entire town. Priest, Priestess, and Hicks find their trail and follow them, eventually catching up to their train. Hicks finds out Priest is actually Lucy's father; he was recruited into the Order by the Church right after Lucy was born and had to leave her and Shannon. Owen stepped in to be Lucy's father and married Shannon.
While Priestess plants a bomb on the railroad tracks in order to stop the train, Priest and Hicks board the train and confront Black Hat and the vampires and familiars (people infected with a pathogen that makes them subservient to the vampires). Black Hat overpowers both Priest and Hicks. Black Hat(whom once was a Priest) reveals that the vampire Queen gave her his blood, turning him into the first vampire-human hybrid and asks Priest to join him; Priest refuses and fights Black Hat, who reveals the truth of Lucy's parentage to the girl. After the explosives are damaged in a fight witht the familiars, Priestess straps the bomb to her motorcycle and crashes it into the train. The explosion kills the vampires and incinerates Black Hat, but Hicks, Priest, and Lucy are able to escape.
Priest returns to the city and confronts Orelas, telling him off the burnt train containing the vampires bodies. He proves this by throwing a vampire head onto the floor; but Orelas believes that the war is over and Priest tells him that its just beginning. Orelas refuses to hear Priest, so he exiles himself from the city alongside Priestess, and discovers that all the priests have vowed to follow him into battle against the vampires. Priest sets off with Priestess to meet the other priests.
