Ross Ricardo Ramirez-Martinez and Takiji Shinkai are on a camping trip when they meet a mysterious fox. From there they find themselves in the town of Ponyville. They discover that some of Ponyville's residents have gone mad, and that cracks and crystals have grown.
Twilight Sparkle meanwhile is studying Clover the Clever's last spells when she finds a warning. It talks of beings that eat and create and destroy. Twilight starts investigating the words, discovering that all of Equestria is in great danger.
Rainbow Dash broke her wing, and so is in the hospital. While there she starts seeing cracks in reality. A fight with a deranged pony leads her to investigate the cracks, finding nothing but distortion beyond them
A 1970's real life/MLP crossover, based on a recent unfinished GURPS campaign I ran for my cousins.