The unending rivalry between Mokou and Kaguya never ends, but when Eirin hatches up a plan to make Mokou's life a living hell, everything changes -- and how will her friend help her recover?

Reisen has known her ability to manipulate insanity and wavelengths for nearly her entire life, but when she uses it on the wrong person that suddenly causes it to backfire, she experiences episodes of temporarily lunacy. Many actions that she later regrets takes place...

Reimu Hakurei, the Shrine Maiden of Gensokyo, was entrusted by Yukari to uphold and preserve the balance, resolving incidents whensoever they occurred. But that trust was bound to be broken at some point, as the old saying goes "You either die a hero or live long enough to see yourself become the villain."