It’s about a goodhearted boy named Takashi who murdered his teacher at age of 13, to protect his childhood friend Yui. The story revolves around tragedies happening to both of them because of that incident.

Utsutsu and Yume Hasegawa have been living all on their own. One day, Yume sees red butterflies and something strange happens to her body!! As the siblings are toyed with by “Pupa,” so begins their tale of...