Twilight uncovers an ancient evil in a dark room of the royal castle. In the midst of a struggle to find herself to become a leader, she follows a voice that leads her down a dark path. Will she be able to escape the darkness in time, or will Equestria fall to the shadows?

Pinkie has Rainbow over for lunch, and gives her a cupcake. Stupid stuff ensues.

What was in that cupcake?