After Sunset Shimmer cleansed the human world of Phyrexia’s influence, she finds herself faced with a new reality: a world where every living human has access to their magical powers. But though the plane of Anthropia has long been known to be deeply entwined with Equestria, even those who have traveled between both worlds do not truly understand the nature of the connection.

When the human Twilight discovers the fossilized remains of an alicorn, her Equestrian counterpart is sent down a path that will unravel a secret hidden for two-hundred millennia. As an unexplained phenomenon causes Equestria’s mana to slowly fade, Twilight discovers not only the forgotten history of both worlds, but the machinations of an elder dragon intent on destroying everything she holds dear.