When Twilight & Applejack are called to Canterlot for an important meeting, the unicorn is worried about how her down-home friend is adjusting to the different society outside of the challenging meetings with Princess Luna, Celestia having gone to investigate a colony of ill ponies.

Celestia is put out of action, and soon zombie ponies are closing in upon the capital. With Luna still recovering from her internal battle with Nightmare Moon, Twilight, Applejack, and a secret society of high-class ladies are all that stands between undead equines...and Canterlot.