In an Equestria overrun with changelings, a mare has taken a stand to say "no more." She will gather allies and take the fight to Queen Chrysalis, no matter the cost.
In the midst of a war with the Crystal Empire, a lone night ranger stumbles upon a strange unicorn, a mare who claims to be the cause of all their pain and suffering.
Sunset Shimmer returns to Equestria only to find Twilight Sparkle battling a strange pony named Starlight Glimmer. Unbeknownst to Sunset, Starlight has altered the past, forcing Sunset to deal with reigniting her friendships all over again.