Residing within Tokyo's district of Ueno are the Colors, three individuals who protect their city by performing good deeds and aiding their community. Or, at the very least, they pretend to be the city's defenders. In reality, the Colors are just three young girls: the shy Yui Akamatsu, the noisy Sacchan, and the video game-loving Kotoha, who spend their time playing make-believe and exploring the city. The Colors' activities are facilitated by the grandfatherly Daigorou "Pops" Kujiraoka, who uses his store's inventory of knick-knacks to entertain the rambunctious trio. Not everyone is a fan of the Colors though. The local policeman Saitou just wants to deal with his regular duties, but he often finds himself the target of the Colors' attention, having been made the villain in most of their fantasies. But despite his personal feelings, Saitou always finds the time to go along with the three girls' games. Even though the Colors do not actually defend Ueno, they definitely help brighten everyone's day. [Written by MAL Rewrite]

High school student Sora Kashiwagi is accustomed to receiving bizarre presents from his father, who is on an expedition around the world. Unfortunately, these gifts have been nothing but nightmares. As a result, when his father sends him a huge package from Egypt, Sora prepares himself for the worst, only to be greeted by Mii-kun—a cute, pint-sized mummy! While initially wary, Sora soon learns that Mii-kun is harmless, a delicate creature yearning for attention. Throughout their amusing day-to-day lives, the unlikely pair meet other people with unique pets, while also strengthening their bond together. Although keeping a pet is a difficult task, Sora is set on caring for the lovable Mii-kun. [Written by MAL Rewrite]

In the distant past, a war between humans and demons brought about widespread chaos and bloodshed. To put an end to this seemingly endless conflict, Demon King Anos Voldigoad willingly sacrificed his life, hoping to be reborn in a peaceful future. In preparation for their king's return, the demon race created the Demon King Academy, an elite institution tasked with determining Anos' identity when he reawakens. He reincarnates two millennia later, but to his surprise, he soon learns that the level of magic in the world has drastically waned during his absence. Moreover, when he enrolls at the academy to reclaim his rightful title, he finds out that demonkind remembers him differently. His personality, his deeds, and even his legacy are all falsified—masked beneath the name of an impostor. This "lack" of common knowledge renders him the academy's outlier—a misfit never before seen in history. Despite these drawbacks, Anos remains unfazed. As he sets out to uncover those altering his glorious past, he takes it upon himself to make his descendants recognize that their ruler has finally returned. [Written by MAL Rewrite]

The story takes place in the second half of the 19th century, as Japanese culture gains popularity in the West. A young Japanese girl, Yune, accompanies a French traveler, Oscar, on his journey back to France, and offers to help at the family's ironwork shop in Paris. Oscar's nephew and shop-owner Claude reluctantly accepts to take care of Yune, and we learn how those two, who have so little in common, get to understand each other and live together in the Paris of the 1800s.