The story of Let's Go Kaiki-gumi follows a nameless protagonist who is six times more vulnerable to spiritual phenomena than the average human being. One day, the protagonist encounters Mechako, a mysterious girl who runs the Kaiki-gumi, an organization that polices the behavior of the ghosts and monsters that threaten human beings, and he somehow gets roped into helping the Kaiki-gumi re-establish itself, resulting in all sorts of strange events and spooky shenanigans.