Based on Akagawa Jirou's popular book series about hapless detective Katayama Yoshitaro who lives with his sister Harumi and their cat Holmes, which has a sixth sense when it comes to solve mysteries. In this stand alone OVA the aftershow party of Harumi's acting troupe becomes the showplace of murder and tragedy. Luckily Yoshitaro brought Holmes along.

Years after the events of Megazone 23 II, the only city on Earth is the supposedly idyllic Eden. There lives Eiji Takanaka, a B Level hacker who has just been accepted into EX, the organization that controls Eden. However, before his first day on the job, he becomes embroiled in a network war, a legendary figure named EVE, and a plot to re-inhabit the Earth.