With Sam Raimi's first offering, like a lot of good horror movies, the unknown actors and the low budget seem to make for a better movie.  A tip for the bigger budget, special effects big wigs of the horror movie genre there: if you want to make a really scary movie, get unknown actors and work on a shoestring!  This school of filmmaking would also work for The Blair Witch Project almost twenty years later.

A bunch of friends, Ash (Bruce Campbell), Scotty (Hal Delrich), Linda (Betsy Baker), Cheryl (Ellen Sandweiss), and Shelly (Sarah York) head for a small cabin in the woods for the weekend. Soon after they arrive strange occurrences begin to happen. Cheryl is sketching the clock in the cabin's living room; and she ends up drawing some kind of satanic book.

That evening, while they're at the dinner table, the cellar door opens.  Ash and Scotty go down into the cellar to investigate and discover the Necronomicon - the Book of the Dead!  They also find a tape recorder, which when played is someone reciting evil passages.
These passages - unknown to them - unleash evil forces in the woods.

Later while brushing her hair in her room, Ellen, hears voices. She follows them, out into the woods, and gets raped by the branches of the trees.

The evil forces possess each person one by one, turning them into demons.  According to the tape, there's only one way to dispose of these demons - full body dismemberment!  What fun!  Shelly gets chopped to bits with an axe, Scotty gets his eyes gouged by Ash, who gets a bit handy with his thumbs!  Linda's head also gets the chop - with a shovel!

Evil Dead is a brilliant, terrifying horror movie with lots of gory effects and great camerawork.  It spawned two sequels, Evil Dead 2, and Evil Dead 3: Army of Darkness, set in medieval times!