The protaganist, Nagao Shuu, lives an uneventful life as a student. But one day a member of the Mystery Club, which Shuu also belongs to, gets a request- “I want you to investigate my big brother, he’s been acting weird lately.”

Shuu and his friends start investigating immediately. Strange things start happening, and they gradually get involved in a more serious case.

What does fate want from Shuu?

Is there any connection between this case and the mysterious transfer student who appeared at the same time?

When the sky is stained blood red, the “Kakuryo” appears...

[Translation of synopsis from Getchu.com]