While on tour with his rock band Slash, lead singer Mac is informed that his aunt died and his family is expecting him on their farm, where he spent his childhood, for the funeral. The group travels in their bus and meets the weird patriarch and Mac's father Jeremiah. The local Billy Bob tells about an old tradition called "harvest of blood" used to improve the harvest. Their bus has problems with the injector and they get stuck on the farm, while a serial killer chases each one of them to collect their blood.