Beyond is, hands down, the best of the Animatrix shorts, a simple story about a woman who explores a "haunted" house in search of her missing cat. It's a bit difficult to understand if you haven't seen The Matrix Reloaded, but it does address one point that was made in that movie that I had hoped they would go into in more detail, namely ghosts, vampires, werewolves and other paranormal phenomena being entirely the result of a glitch in the Matrix. Beyond is a haunting piece reminiscent of the "Labyrinth" segment of Neo-Tokyo, an obscure anthology of anime shorts by Rin Taro (Metropolis), Yoshiaki Kawajiri (Ninja Scroll) and Katsuhiro Otomo (Akira).