“What do you think it is this time?”
“I don't know, Applejack. She appeared out of the blue, told me to drop whatever I was doing, fetch you four, and go to the place marked on this map, without telling anypony else. She said that she had to prepare a few more things and would meet us there, took Spike with her, and went out in a hurry. She gave me no chance to speak at all! Not. A. Single. Word!”
“I just hope she has not gone crazy again.”
“She was very agitated. It was as if she had seen a ghost!”
“A ghost? Hah! If it is a ghost, it does not have any chance. I can totally take it on!”
Applejack glared at Rainbow Dash.
“I just hope it's not something dangerous.”
“Don't worry, Fluttershy! No matter how strong it is, we will kick it in the flank in no time! Like we always do!”
“And if it is a ghost, we will laugh at it! And sing and dance and invite him to a party! Oh, there she is!”
The five ponies arrived at an open field next to the town, where Twilight Sparkle was waiting for them.
“Thank Celestia you all arrived. We still have enough time.”
“Twilight darling, could you please tell us what is going on?”
-*-*-*-
“Twilight Sparkle.”
“I must be hallucinating,” thought Twilight Sparkle. “Perhaps I did make a mistake in the potion or the spell after all.”
“No, you are not hallucinating,” said the reflection.
“Then how...”
“Listen.
“The Equestria you live in is not the only Equestria that exists. There are many Equestrias, all floating on an endless void beyond space and time. They are different, yet similar. Their difference might be large, or small.
“Within this void, also live undescribable creatures. Unbounded by time and logic, some of these creatures live to devour worlds like ours.
“Our Harmony protects our Equestrias against these creatures. Unfortunately, one event happened which weakened our defenses.
“In one Equestria, these monsters found a small crack. It was too small for them to enter. But they touched it.
“The results were horrific. A happy pony was turned into a murderous cannibal. When she killed her best friend, the Harmony in that world shattered. The world split itself into many copies, each with a different history. Some of these copies recovered enough Harmony, and survived. Others lost all of their remaining Harmony, and were devoured.
“There were even worse consequences. When that world was broken, sympathetic resonance caused cracks to form in other Equestrias. These abominations were now free to touch other worlds, damaging their Harmony and allowing them to be eaten.
“My Equestria was one which managed to keep its Harmony strong enough to repel these creatures, even though it also had a crack. When I found out about that, I decided that it would be my duty to help other worlds keep their Harmony. To warn them before it was too late.
“Your world was destined to be lost, until somepony else from outside interfered. Now it can still be saved, even though it will not be as perfect as it could be without their taint. However, it can only be saved if you can stop yourself from making things worse.”
“What do you mean?”
“You made yourself forget, but I will make you remember. I will tell you what you must do to restore Harmony to your land.”
-*-*-*-
Twilight stopped her narration. She turned and silently cast a powerful spell. The brilliant glow from her horn lighted the surroundings. A loud sound filled the air, as if thousands of sheets of paper were ripped at the same time.
The air twisted. A small dark hole appeared, slowly growing into a vertical fissure. Twilight overlayed a second spell, creating a glowing cylindrical barrier around the fissure.
She turned back to her friends.
“You know how it seems like every month there is a new threat to Equestria. Every time, we have to fight against it, and every time we defeat it.”
“Oh, like the confectionery monster last month? It was yummy!”
“Yes, like that one, Pinkie.”
“I wonder which one will be next? A chocolate monster? A...”
“Please, Pinkie, not now. We do not have much time.”
Pinkie Pie signalled that she would be quiet and nodded. Twilight continued.
“This crack caused all these threats, and they are only going to get stronger. Until, one day, one of us will have to sacrifice herself.
“My future self will then begin to hunt these threats. But she will do it in the worst possible way. Instead of strenghtening our Harmony, what she will do will only do more damage to it.
“She will now attempt to prevent the heroic sacrifice. We have to stop her, and show her that there is another way. We have to show her that we can prevent the loss of a friend, and save our Harmony at the same time.”
Twilight pointed at the crack.
“A few months ago, I was experimenting with a teleportation spell. This crack interfered with it, turning it into a time travel spell. We were sent to the future.
“We do not remember because my future self blocked our memories, before sending us back. The other me gave me a counterspell, so that now I can remember.
“I did not want to have you girls remember too, but there is no other way. I am sorry.”
With little warning, she fired the memory spell. Memories flooded her friends. They remembered being sent to the distant future. They remembered meeting their distant relatives. They remembered learning about Rainbow Dash's death.
“Here is what we will do. First, I will use this crack in time to send us to the future.”