Fluttershy has noticed some new vicious bunnies around and wonders where they�re coming from. When her pet Angel disappears, Fluttershy gets worried and decides to investigate further. To do this, she asks Twilight to turn her into a bunny. Twilight concedes, but she insists on coming with her. Together, Twilight and Fluttershy search for Angel in an unknown warren that may be harboring a dark secret.

Crossover with--say it with me--Watership Down, which if you get it should explain the dark tag.