Young Bobby Cromwell had no idea what to expect when his adoptive parents took him hiking in the eastern Oregon wilderness, but when they decided to scale the rugged terrain around Mount Eras to catch a spectacular view of the Blood Moon, they stumbled on something more sinister: an old legend that slaughtered the living and devoured their flesh. Spared the fate of death, Bobby was allowed to escape that fateful encounter, but only under the oath that he would lure additional victims to the mountain once a year, when the Blood Moon would allow the spirit to be its most ravenous. Now an adult and scarred by the part he has played in the massacre, Bobby has brought seven 20-something acquaintances to the fabled Blood Mountain, where mayhem ensues as they stumble on the same evil and wind up in a frightening push for survival.