When The Evil Dead was first released it was hailed as one of the most original horror movies ever. This was mainly down to the fact of the way the evil (or deadites) the group were up against acted. While it may be influenced by George Romero's movie there are many original ideas used.
The deadites were awoken from their ancient slumber when Professor Knoby reads aloud the passages from the book of the dead. Now they lurk in the woods around the cabin searching for human victims who they can possess and take back what was once theirs, life.
It now seems the only way to rid those possessed by the evil demons is through the act of bodily dismemberment. So it's up to Ash and his friends for find a way to rid the world from the evil of the deadites once and for all.