Spiral: Suiri no Kizuna  

Spiral, Spiral ~Bond of Inference~, Spiral ~Bond of Reasoning~, Spiral ~Suiri no Kizuna~, Spirála, 스파이럴 ~추리의 띠~, スパイラル -推理の絆-

Kiyotaka Narumis older brother, who is both a famous detective and pianist, mysteriously vanishes without warning. The only piece of evidence that Narumi has left behind are the Blade Children. Two years later, a series of murders and events occur that seem to be linked to these mysterious figures. Along with Hiyono Yuizaki, a school journalist, Narumi embarks on a quest to uncover their fate.