Looking for a cinnamon substitute, Applejack brings Dash out into the Everfree forest. While there, the ground opens up and takes them into another world with new ponies, new dangers, and a war, centuries old. And this battle certainly won't stop for the two confused mares.
Yes, this will eventually lead to Appledash.
Thanks a whole lot to TheShadow for editing and general helpfulness while working on this thing.