The Canterlot Three Games is an event between the three original Equestrian cities of Canterlot, Manehattan, and Cloudsdale. A long time ago, two ponies entered, and won a series of sporting events.
Applejack wants to follow in the footsteps of her parents and compete. Coached by a grumpy games inspector and shadowed by the Wonderbolts newest member, she begins a series of unorthodox training methods to get her ready to measure up to some of Equestria's most intimidating athletes.
Teen for some somewhat more mature-ish concepts. Oh, and cheers to pre-readers Tchernobog and The Yaoi Mistress!