Twilight Sparkle has been attending Canterlot Academy of Pokemon Studies since she was a child. Now in her late teens it is time for her to undergo a right of passage many ponies her age have already undergone: The Equestria Gym Circuit. Eight gyms, the Elite 4, and a Champion. Completing this challenge proves you know and love Pokemon and are capable of living in the world of Pokemon.
Of course, for Twilight, she never wanted to go on the journey to begin with... and nothing is ever easy.