Eerie and Artless Enclosed World

The first installment of the Sekai Series. Two siblings in the process of crossing a forbidden line, Hitsuuchi Samatoki and Hitsuuchi Yorotsuki. Two friends, Mukaezuki Hakohiko and Kotohara Ririsu. A locked-room murder at the school cracks their worlds… (Source: Kodansha, translated)

The third instalment of the Sekai Series. Byouinzaka Kuroneko and Hitsuuchi Samatoki received a strange consultation and are invited to London, the city Sherlock Holmes loved. The mystery-solving battle of the incidents that occur one after another has begun! (Source: Kodansha, translated)