Spiral is a series which starts off telling you about Ayumu Narumi's older brother Kiyotaka, a renowned detective and piano player who, all of a sudden, disappeared. Two years later a row of murders and incidents begin, relating to the Blade Children. What are the Blade Children? This is a question Ayumu Narumi has been asking himself since his brother’s disappearance.
But today isn't a day to bother with that as Ayumu has been accused of murder. While he tries to defend himself against growing allegations, Ayumu must unwrap the mystery of his innocence - as well as the mystery of the new professor who seems determined to pin this crime on Ayumu…