Three years ago, Sunset Shimmer was sent to an all-girls boarding school with no explanation from her mother, other than the explicit instruction to not return until she reaches eighteen years of age. On the eve of her fifteenth birthday, she goes against her mother's instruction if only to see her again after so long, but waiting for her is another.

A mysterious gentlecolt, under the guise of a lodger, has been waiting for the young mare all this time. His reasons, however, he keeps to himself. Sunset soon finds herself in the midst of a sinister plot that dates back hundreds of years, and the only way to stop it is to fight. Armed with a bottle of holy water and a magical bow, can the unicorn protect herself and save her mother from this man, or will she fall victim to him and his subordinates?