Prologue: Equestria
"Man.. I'm beat..." AppleJack said as she walked slowly back to the farm, "How in tarnation does Pinkie Pie throw such a great party on such short notice?"
The orange earth pony barely remembered what she said to her brother and sister before she went to bed. She woke up and checked her clock, 12:34 "Land sakes!" She leapt to her hooves and ran out the door, headed for the orchard. Big Mac was out at a meeting for his speech club, and AppleBloom was at school. Fortunately for AppleJack, Big Mac had cleared about half the apples they needed to clear before she'd even woke up.
The heat was beating down on the orchard, prompting AppleJack to grab her saddlebag and put a couple of water bottles inside with a notebook. She went into the trees with her bushels and carts, beginning to buck. The day seemed uneventful, other than sleeping in. Until a thick leather-bound book fell on her head. The pony looked over the book, confused, "What in tarnation..." She slipped the book into her saddlebag.. And promptly forgot about it.
AppleJack finished putting the apples in the storage cellar, and went straight to the farmhouse. As she reached towards her saddlebag, she felt the book from earlier, and brought it out to take a look. It was bound in green leather, with simple black lettering on the front cover: "MYST."
Upon opening the book, AppleJack saw weathered pages and, on the first page, a panel that would look like a photograph if it weren't for the fact that it was a spinning view of a turtle-shaped island with a tower at one end and a forest at the other.
She couldn't shake the feeling that there was something different about that panel. Looking through the rest of the book would show no hints of circuitry or magical symbols. Finally, she placed her hoof on the panel. There was a lurching feeling in her stomach, as she fell into the image.