In the introduction, a hillbilly woman is (somewhat disturbingly) beaten and killed by who appears to be her violent ex-boyfriend, before said goon is killed by the lady's son. I'm still in the process of sorting out how this fits into the whole storyline, but maybe that's pointless, as proved later.
A few decades later, that same son has grown into a bearded and broody hunk. He's part of a group of disparate individuals heading to the desert for some sort of spiritual enlightenment trek. There's a preacher and his dull girlfriend, the goofy best friend, the sports fanatic, 2 bimbos, 2 worthless goths, a fat foul-mouthed lady, etc.. Halfway through, their bus breaks down and they hike to a ghost town. The same ghost town that, earlier on, a salesman "bought" the rights to the Death Factory Museum from an unsuspecting local. The poor chap must have been the only left resident in town. After some accidental sexual witchcraft, the 2 goths awaken the spirits of legendary serial killers like Ed Gein, Jack the Ripper, and a a healthy handful of others (including a bare-chested lethal vixen I couldn't recognize, but maybe she was only there for gender equality). The broody and hunky son makes it a mission to save his reluctant posse by absorbing the spirit of said killers, then there's some capoeira, and the Devil, and it just stops making sense.
If you agree to not try and make sense of the very messy storyline, you will probably be pleasantly entertained by the varied shenanigans. All the killers have great presence (except maybe for the aforementioned vixen, probably because she has no back-story in our collective pop consciousness). They are strongly portrayed, have threatening presence, and are prominently featured. There's lots of actions and gruesome killings, some refreshing nudity, the plot twists keep on popping until the very end, there's nothing to be bored with. Just leave your expectations at the door and enjoy the heartfelt ride.