Mondays sure suck, don't they? You wake up early, brush your teeth, try to get ready for your miserable job, step outside-and plummet to your death. Okay, so maybe this Monday was a little worse than most.

Rainbow Dash arrives in a dark and endless abyss without any memory of how she got there. The only thing she can recall is waking up on Monday and falling to her death, nothing beyond that. But no matter, there is one other being there who might be able to help out. His name is Discord, (who is now apparently going by the name of 'God of the Afterlife") and he takes her on a journey through her memories, unraveling them one by one in order for Rainbow to move on.

Day 10.

It's dark and cold. The sky is dead. I'm okay.

Day 50.

It's deep, stretches on forever. The craters eat me up. Life goes on.

Day 100.

The sky is closing in on us. We're fighting but we're losing. The whispering won't stop. The chains rattle on.
I want to go home.

When Rainbow ends up stuck in a hospital bed after flying through an unschedualed, violent storm, she gets to know the mare in the bed next to hers. A light grey pegasus named Derpy. A pony who tries so hard to learn, so hard to understand the world but has difficulty remembering and processing new skills. A pony who's wanted nothing more all her life than to be smart, accepted, normal.

When news of a new experimental spell said to increase intelligence begins to spread, Derpy is the first to jump at the idea. Rainbow does everything in her power to help her friend, and with some encouragement from Twilight, the wall-eyed mare is chosen for the experiment.

On the wake of a nightmare, Twilight finds herself trapped in a strange and disturbing place with no explanation of how she got there. She has no memory of the night before, no understanding of how this could be. And she is not alone. Many ponies—mares and stallions, all around her age, have been taken from their homes by ponies who promise they are all part of something 'divine'.

She and the others are forced to participate in tests, both mental and physical, fight and run through brutal mazes. The only thing Twilight has to keep her mind together are the bonds she's managed to form with others and the hope that her friends will come to the rescue. But this place is far more sinister than she knows. Not until ponies are taken away for "Advanced Testing" does she realize just how hopeless her situation is.

Meanwhile, life in Ponyville goes on as always... as though Twilight had never existed at all.

He came in the dark of the night. An ominous figure watching from above, ready to strike at any moment.

Rainbow had been told the story as a filly. The story of the Lurker, a monstrous creature who preyed on mares late at night. It was certainly a scary thought but was it true? The young pegasus hadn't even considered it when she told the tale to Pinkie Pie one sleepless night. But when mares start to go missing, doubts settle in.

Is the legend of the Lurker really true?