After the sudden Horde attack on Ponyville, Twilight Sparkle visits the injured Princess Celestia in hospital where she, and the other Bearers of the Elements of Harmony, are given a mission.

To travel to the world the Horde came from and learn all about the way they use magic, so that better defenses against it can be developed.

Arriving at their destination, the six friends find themselves caught in a twisted web of deceit and betrayal. And soon, the drums of war are sounding ominously close to home...

AUTHOR'S NOTES

Rated Teen for violence.

Comments contain spoilers.

This is the sequel to Horde in Equestria, so I suggest you read that first. The third and final part of this trilogy can be found here.