The BLU Medic has a problem. Ever since the last Halloween, he's been trying to teach his team about magic, but they won't stop rambling on about this 'pony' thing, or stop watching it.

So, when he argues against friendship, Merasmus decides to both teach the Medic's team a lesson and pull a prank on them. Using a spell, Merasmus sends them in the body of their pony counterparts to Equestria.

Unfortunately, their pony counterparts already live the land of Equestria. And most of them go by the names of the Element of Harmony...

Meanwhile in Equestria, an enormous magical pulse has appeared, causing the royal wedding to be cancelled. Twilight and her friends must discover the source of this disturbance, and determine whether it's dangerous or not.

In the shadows, however, lurks an army that have waited millenia for this moment