A young woman wakes up in an unknown Western house and is attacked by hideous monsters. As she runs away she wonders where she is, and who she is, as she has lost all memory of her past. She finds other men in the house who are in the same circumstances. All the inhabitants hold mysterious handguns. The protagonist and the young men must risk their lives to take part in a “black butterfly hunt,” and gather the “fragments of kaleidoscope” that the monsters possess.