Crossover with Avatar: The Legend of Korra.

After finally connecting to her spiritual side and getting her bending restored to her Korra restored Lin Beifong's earthbending. Something went wrong, however and she vanished in a shockwave coloured with a rainbow.

At the same place, minutes after, a pony was found in a hole. A pony who is a bender and is also the new Avatar.

The Legend of Korra has ended but now begins the Fable of Quaker