Biocatalyst is a short horror visual novel set in the late 1990s with a PC-98 aesthetic.

Kazuki is an average wage slave crunching away on a Friday night with two of his coworkers. As if working unpaid overtime wasn’t horrifying enough, the trio receives a strange email containing a cryptic message about "revealing the truth"; fail to do so, and they'll be killed at midnight. While they brush it off as a prank at first, after they get trapped inside the office with no escape, they soon realize they're in for a rough night. With a vengeful spirit now actively hunting after them, Kazuki and his coworkers conclude they better unveil the mystery of their company before the clock strikes twelve - or die trying.