Title: Power Ponies: Nightmares Reborn

Main characters: The Power Ponies, Mane-iac, Princess Celestia, Princess Luna, Princess Cadence, Shining Armor, Nightmare Moon.

Genre: Alternate Universe, Dark, Adventure, Romance.

Premise:
Millions of years ago, when a trio of Alicorns ruled the land, an ancient darkness attempted to corrupt one of the sisters. With the help of the older and younger sisters, she was saved and the darkness was defeated and sealed away in an ancient relic known as the "Crescent Crystal". However, millions of years after their passing, the relic was discovered...

In present day, the Power Ponies catch Mane-iac and her goons attempting to steal the "Crescent Crystal" from the Maretropolis Museum. During the fight, Humdrum accidentally drops the artifact, shattering it and releasing the ancient evil locked inside:

Finding herself in a new time period with no one to stop her, she quickly and easily defeats the Power Ponies and takes over the Mane-iac's gang, forcing them to serve as her minions and reducing the Mane-iac to a pathetic lackey. Eventually she starts her plans to take over Maretropolis and the rest of the world.

Despite their best efforts, the Power Ponies are completely powerless to stop her. But upon discovering book detailing the entity's first defeat, they find out that they must acquire 3 relics that are laced with the power of the original Alicorn sisters original magic. Allied with a new Power Pony, they must find these relics before their new enemy does!

However, the relics won't just let anypony wield them...

3257662 Hey dude me and a friend could do this idea if you want. We can work on it while you and I do that other thing.

3258689
Sure! Can we discuss this via PM?

3259134 Sure.

3257662 Are Princess Luna and Nightmare Moon separate entities?

3261999
Yes.