Batsy Fluffentuft (not the most respected of the lunar guards, and in fact on super-probation from Princess Luna herself) manages to escape into the town of Canterlot and have herself an adventure.
Based on this story:
The Great, the Powerful, and the Magnificent
Batsy Fluffentuft the Magnificent's Grand Shower Quest
Batsy Fluffentuft's Short Screwy Adventure
Batsy Fluffentuft the Magnificent Becomes an Alicorn
Batsy Fluffentuft the Magnificent gets out...again