The forces of the Demon Lord rightly tremble in fear of the Crimson Demons - the powerful clan that produced both Megumin and Yunyun. Their mastery of advanced and overwhelmingly strong magic is unparalleled, and even the Demon Lord's generals would struggle to vanquish them. Upon receiving a grave-seeming letter that predicted catastrophe for her hometown, Yunyun enlists the help of Kazuma Satou and his comrades. After some initial confusion, they discover that the letter was nothing more than a prank by a collaborating demon who harbors aspirations to be a writer. Nonetheless, Megumin is worried about her family's safety and decides to lead the group on a journey to the Crimson Demons' village. Once there, Kazuma and his companions set out to take in the sights of Megumin's birthplace. Yet, it gradually becomes evident that the ominous threat in the letter may have been more than just a playful tease.