After being missing for months Rainbow Dash returns to Ponyville and her love Applejack...but she's different. She is cold as ice, stronger than steel and has an insatiable craving for blood. Applejack still can't let her go, no matter what she has become. When a group of monsters, just like Rainbow Dash, pursues them, all of Ponyville and everypony that Rainbow Dash loves is at risk. Can she resist the urge to join them? Can she protect all the ponies she loves? Does she have the heart of a monster...or a pony?

(NOT inspired by Twilight (the book), it is inspired by the Swedish book/movie Let the Right One In or Let Me In.)