Spiral: Suiri no Kizuna

Ayumu Narumi has always measured himself against his brilliant older brother Kiyotaka. When Kiyotaka vanishes, his last reference to the Blade Children becomes the only lead in a mystery Ayumu cannot leave alone.

A suspicious incident at school draws Ayumu into a series of dangerous tests. With the energetic Hiyono Yuizaki beside him, he must use observation and deduction to confront people who seem to know far more about his brother and his own future than he does.