Five years ago, Maha Igarashi took a late-night train to attend a flash mob event organized by an occult forum — and vanished after stepping off at a station called Kisaragi, which then disappeared entirely. Her boyfriend Shizuno Yokoyama never gave up searching. He opened a detective agency specializing in unusual cases, all hoping to find a trace of Maha. The deeper his investigation goes, the more entangled he becomes in a mist of layered mysteries.