Jinpachi Tanaka is a paranormal investigator who possesses the powers of detecting and fighting demonic creatures. As these demons are usually female and pretty, they can easily pose as humans, and Jinpachi must use somewhat unorthodox techniques to tell friend from foe. Jinpachi and his employees must cooperate with the police and avert grave dangers posed by an angry female demon who has sworn revenge against the hero.

Bacta is a Japanese-style adventure game. The player is presented with a text menu containing verbs, most of which lead to sub-menus with objects. Some of these commands are context-specific, while others ("Look", "Talk", "Move", etc.) are present in every situation. Sometimes events must be triggered by repeatedly selecting commands.