The Hatomura twins are constantly switching places, and Totonou has been tasked with finding a way to tell them apart once and for all. But everything changes when he stumbles upon the family's dark and dangerous secret. Totonou soon figures out how to tell the sisters apart, but by revealing it is he putting the girls in danger? Then, when Detective Aoto's daughter is kidnapped, he finds himself teaming up with Totonou to get her back.

When Totonou's favourite professor asks him for a favor, the usually introverted Totonou can't help but say yes. Professor Amatatsu is planning a weekend getaway in the snowy countryside. Once all the guests are assembled, one of them suggests they play a murder mystery game. But as the snow continues to fall and people start to act more and more strangely, Totonou starts to suspect that this isn't a game at all!

Kunou Totonou keeps finding himself right in the middle of mystery after mystery. After taking a tumble down a hill, Totonou is hurt and ends up in the hospital. There he meets a beautiful young woman named Leica. As he follows her coded instructions, he uncovers a disturbing urban legend about an 'Angel of Embers' who's made it their mission to save children. But who exactly is this 'angel' and what are their true intentions?