Keiichi Maebara has just moved to a seemingly peaceful new town. He's making friends and generally enjoying his life until one day he learns of a grisly murder that took place in the little village. His friends won't give him any details, which only adds to Keiichi's uneasiness. After learning at the town's annual festival that a death has occurred on that night every year for the past four years, Keiichi is drawn into a web of intrigue to help unravel the mystery of these murders.

The further embroiled in the investigation he becomes, the more Keiichi's suspicions about his new friends grow. Their strange behavior only gives rise to more questions. Keiichi's paranoia reaches a fever pitch... with good reason. Assaulted by one terror after another, he nears the inevitable, bloody solution to the series of mysterious deaths caused by "Oyashiro-sama's Curse"!

You've already met Keiichi Maebara and his mischievous friends in the Abducted by Demons Arc. But Oyashiro-sama's curse is poised to strike anew in Hinamizawa village. When Keiichi spots tomboy Mion working at a maid café, he can hardly believe his eyes! But it's not Mion after all - it's her identical twin sister, Shion.

Twins Shion and Mion have Keiichi seeing double. But as he grows closer to Shion, their flirty friendship has Mion seeing red. When Shion and Keiichi trespass on sacred ground the night of the Cotton Drifting, a string of gruesome murders and disappearances follow. Are the legends of Oyashiro-sama's curse true? Is there a demon in Hinamizawa?

After a short trip to the city, Keiichi Maebara returns to the small mountain hamlet where he is welcomed with a fresh batch of pranks from Satoko and the rest of his school friends. Satoko may be the youngest of the group, but she always puts on the biggest smile. Who knew her upbeat attitude masked a terrible tragedy - a year ago her older brother, her only family, vanished without a trace.

"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.

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.