It is not strange that the Demon Lord's forces fear the Crimson Demons, the clan from which Megumin and Yunyun originate. Even if the Demon Lord's generals attack their village, the Crimson Demons can just easily brush them off with their supreme mastery of advanced and overpowered magic. When Yunyun receives a seemingly serious letter regarding a potential disaster coming to her hometown, she immediately informs Kazuma Satou and the rest of his party. After a series of wacky misunderstandings, it turns out to be a mere prank by her fellow demon who wants to be an author. Even so, Megumin becomes worried about her family and sets out toward the Crimson Demons' village with the gang. There, Kazuma and the others decide to sightsee the wonders of Megumin's birthplace. However, they soon come to realize that the nonsense threat they received might have been more than just a joke.
In order to take over her grandmother's Dagashi store, art student Kumi Honamanuma moved to Kyoto. She met Harami Mino, K Kusanagi, Mai Haisaka, and a dog who lives in the store, which supposed to be empty. Kumi ended up living with these girls, who claim that they are heroes reincarnated to contemporary period to chase after the demon king. Harami and others seem to live in a peaceful life with no missions to to do anymore, Ran, who was demon king in the past and appears to be an elementary school girl from failing to reincarnate, one day. The story begins with Ran requesting to collect demon king's fragments.
Third-grader Himeno moves to a huge mansion in the country. However, she soon finds out it's a ninja house! The ninjas Akamaki, Aomaki, and Kiiromaki mistake Himeno for a princess and begin solving problems for her with their own unique skills. But that is not the full extent of their powers! When Aomaki and Kiiromaki combine, they form Midorimaki. Similarly, when Akamaki and Aomaki combine, they form Murasakimaki; and when Akamaki and Kiiromaki combine, they form Daidaimaki. Life with these colorful ninjas has only begun when they discover a large tornado heading for the mansion. What will happen to Himeno's family? Can the colorful ninjas protect Himeno?
In an age when large-scale natural disasters frequently happen all over the world, when cyborgs and autonomous robots are beginning to appear on the market in technologically advanced nations, and major world powers compete for technology and resources, the divide between rich and poor grows and the future for the poor looks bleak. In this transitional stage, everyone wanders around in a self-indulgent daze and the way out isn't clear... This is the story of how two cybernetically enhanced girls meet.