A small change results in much bigger difference. Twilight, sent to alternate reality in “The Cutie Re-Mark”, realizes that in order to undo Starlight’s spell, she needs the help of one who created it.

Searching for her, Twilight finds both best and worst versions of not only Starlight, but herself, in many different realities. Forced to see the extremes of both of them, she is forced to ask herself a hard question. Should she try to convince Starlight, instead of fighting her, even if it risks Equestria's future?

But the real question is – can she truly save her?

(Mane 6 only die temporarily and/or in some alternate universes, none of them die permanently in the story despite the Death tag)