21: Two One

Takuya Kirishima is a brilliant young surgeon who can apparently cure anything — and who works daily alongside his childhood friend and nurse, Seri Sasaki. The hospital's equilibrium shatters when a murder is committed in the building on the same day a strange, previously unknown disease begins spreading among patients. Takuya starts digging into both events at once, driven by the conviction that the answer to each will help him protect Seri from whatever is circling around them.