After the defeat of the villains Tirek, Chrysalis, and Cozy Glow, the Cutie Mark Crusaders are curious to know about the Bewitching Bell to see if they can become stronger ponies. It was only after they cast the spell they now have to deal with the first emperor of Equestria, the father of monsters, Grogar

This is more of a "what if" scenario if the Crusaders interact with Grogar so its a story just for fun.