During her brother's surprise wedding, Twilight meets a demon from her past that overturns the lives of everypony around her, and threatens to tear apart their friendships. Meanwhile, Twilight's enemies, old and new, close in as her spirit fails.
Dusk Shine is rather surprised to find himself in the bedroom of one Twilight Sparkle, just after the 1000th Summer Sun Celebration. Shenanigans, guitar solos, and demon forms ensue.