The Ring virus is mutating, and Ando, a medical doctor, must choose between possibly betraying his species and bringing back his drowned son. You don't know what the Ring is yet...

On the very same evening that his little sister and best friend are married, Haruka is assaulted by a mysterious, scarred man who swears vengeance for a past wrong that he claims to have suffered thanks to Haruka's family! Can Haruka nail down the stranger's identity in time to save his own skin... or will his hunt for answers send him spiraling into a vortex of pain and suffering?

"I'm going to uncover the mystery of the 'Blade Children.'" World-class detective Kiyotaka Narumi's last words prior to his sudden disappearance continue to haunt his younger brother, Ayumu. The cheeky tenth-grader becomes further embroiled in the mystery when he is mistaken for the prime suspect in a murder at his school.

Hiyono's gamble has bought Ayumu some time, but is ten minutes long enough to reason out an effective plan? Ayumu kicks his mind into overdrive, orchestrating a series of wave attacks designed to overcome Kanon's incredible fighting skills. But should any member of his already battered team miss their mark, it could mean death for them all. As the players move into position, Ayumu stands to face Kanon in what will be their final showdown.

The battle with Kanon may be over, but it's going to be some time before Ayumu and the others fully recover from the ordeal. As the police and media casually sweep the entire incident under the rug, Ayumu realizes he's no closer to solving the mystery of the Blade Children. But a month in the hospital is a prime opportunity to gather information from his fellow inpatients, who seem ready to confide the secrets of their curse. A dark and dangerous path lies ahead... Has Ayumu grown strong enough to face it?

Ayumu prepares to leave the hospital, still mulling over the murderous role fate has for him to play. But if Hizumi is destined to die at Ayumu's hand, why does he seem so eager to be friends? Far from bloodthirsty, the good-natured Hizumi has been living in Ayumu's apartment since the Kanon incident and intends to stay on as Ayumu's roommate! Hizumi claims to have accepted the cards fate has dealt him, but can he really be so complacent about his own death?

Hizumi's "happy high schooler" facade begins to crumble as Ayumu confronts Kirie about Hizumi's cheerful acceptance of the fate that awaits him. Big brother Kiyotaka has always cast a shadow over Ayumu's life, but what kind of despair has Hizumi known that would make him so ready to die? Hizumi still hasn't laid all of his cards on the table, and his next play could take out one of the Blade Children for good.

When Kirie's DNA tests on Ayumu, Hizumi, and their respective older brothers yield shocking results, the disgruntled Watcher confronts the only two people who can confirm the truth of Ayumu's parentage: his mom and dad. What she learns shakes her to the core, but how will Ayumu react when Hizumi reveals how science has warped their fates? Will Ayumu's resolve to save the Blade Children remain firm, or will anger and despair cause him to waver?

Hizumi makes his final plea, begging Ayumu to accept the fate that has been forced upon them. By killing Hizumi and taking out Kiyotaka before his own natural demise, Ayumu can remove all the supernatural pieces on the board. After all he's been through, Ayumu certainly intends to meet his brother, but will he face Kiyotaka in the name of defiant hope - or broken surrender? That may depend on Kiyotaka, as he reveals his last cruel twist of the plot in the final volume of Spiral.

Ayumu Narumi aggressively pursues his goal to unravel the mystery of the "Blade Children." With every step he takes, though, the path to the truth becomes more treacherous as a conspiracy is reveled. Could it be that Ayumu's fate was intertwined with that of the Blade Children even before his journey began?

When one of Ayumu's teachers promises to give him a few clues about the Blade Children, the deceptively cute Rio, one of the Blade Children herself, ruthlessly murders the man in broad daylight. Faced with another brutal murder to solve and one step closer to finding out what the Blade Children really are, Ayumu and Hiyono find themselves the direct targets of Rio's malice.

To save the kidnapped Hiyono, Ayumu must match wits with two murderous Blade Children... and his genius brother! The showdown between Ayumu Narumi and the Blade Children duo of Rio and Asazuki enters stage two when Hiyono is kidnapped and an intricate challenge involving perfectly timed bombs and blackmail is set before our unlikely hero.