Chimsun Mountain Correctional Facility is a medium-security state prison located in southern Colorado. It houses 1300 inmates, mostly mid-level drug dealers, car thieves, sex offenders, pimps, a handful of completely innocent but unlucky souls, and the occasional murderer. Inmate Jonathan Poke and his road-dog "LIL-T" are two short-timers flying under the radar of prison politics. Both men will find themselves thrown head first into madness and death when they discover an ancient evil, The Manananggal. The Filipino Manananggal is a vampire of sorts. Also known as the Aswang, the Manananggal is a beautiful creature capable of cutting her own body in two. She sends her top half flying through the night in search of babies to devour. Such evil will not be disturbed by the mere presence of consecrated accouterments. Only the touch of a dried stingray's tail will deter her. Only the light of day will destroy her. It is believed by some that human semen is corrosive to the skin of the Aswang. Very few men have been willing to substantiate the claim and of the willing, none have lived long enough to report the truth of it.