A poor university student, Suigetsu Otori, meets Shinya Kojo, a man with an identical face and build. Together with Kojo, a self-styled OOPArt appraiser, Otori investigates a series of murders connected to enigmatic artifacts, including an archaeologist's body surrounded by crystal skulls and a golden space shuttle that vanishes from a locked room.

A traditional mystery in which an identical-looking pair confronts impossible artifacts and locked-room murders.

A police mystery that follows an apparently impossible incident involving DNA through methodical investigation.

Follow the chain of reasoning and the truth comes into view.

A bio-suspense novel that uncovers a terrifying truth through an investigation into a strange tomato disease.

The circle of infection spreads in unseen places.

Sekiguchi Ran, a university student unable to contradict other people, is asked by first-year middle-school student Anju Ito to help stop her reincarnations; she claims to remember her two former lives. When they visit the family home of Anju's earlier incarnation, Momoko Kamiyama, a poltergeist occurs and the household head is found poisoned the next morning, with Momoko's signature left at the scene.

A traditional mystery in which a reincarnated girl and a university student pursue the link between a murder more than thirty years ago and a present-day poisoning.

At Tokubei Nagaya in Edo's Honjo district, people believe that the doll known as Morisama can grant wishes for vengeance. As murders occur across the town, constable Jinhachi investigates with his sister Oshino and childhood friend Yanagijiro, drawing on memories from his own childhood to uncover the truth.

An Edo-period mystery in which a constable pursues the truth behind serial murders linked to a doll said to avenge grudges.