After Rainbow Dash's sudden disappearance and her subsequent discovery in the another world, the Princess and Twilight Sparkle must do all they can to restore the separation between Equestria and the human realm. All traces of Rainbow Dash's presence must be erased, no matter the cost. Her past life must be turned into a forgotten memory.

But can memories truly be forgotten? Can magic destroy fifteen years of experience and emotion? Or will Rainbow Dash be forced to exist with a dual history, the memories of two lives flowing through her mind?

And what of the human?