For as long as he can remember, the klutzy Tsuyoshi Yano has been prone to injury. Constantly showing up to school with fresh scrapes and bruises, he has long become accustomed to the pain and to the sight of his face covered in bandages. However, Yano's days begin to change for the better when he is transferred to a new class and meets Kiyoko Yoshida, the class president known for her reliability and kindheartedness. Through Yoshida's efforts to learn more about him, Yano starts to experience the kind of high school life he has always wished for—one filled with laughter and camaraderie. Between casual conversations and countless small accidents, the two gradually grow closer, and their relationship may bloom into something more than just friendship.

Although Hyouma Kunato has begun to feel comfortable around Botan Nagatsuki and her family of tsukumogami—objects possessed by spirits called marebito—he has not forgotten about his main goal in life: revenge. Unbeknownst to Hyouma, while he is training in Kyoto under the supervision of the Kadomori family, the Bureau of Traditional Music, a group of three musical instrument tsukumogami, begins to enact its plan. The trio questions Botan's family about their intentions regarding Hyouma's presence near the person embodying the frontier between the human and marebito worlds. Soon after, the paper umbrella tsukumogami that Hyouma had been pursuing for years suddenly reappears and abducts Botan along with her university friends. Rushing to save the one he swore to protect, Hyouma might have to change his priorities if he wants to keep his promise to Botan.

Following the revelations of the archangel Gabriel, Ente Isla hero Emilia Justina—who lives on Earth under the alias Emi Yusa—starts doubting the validity of her mission to slay the Demon Lord Satan, now reduced to a modest employee of MgRonald's as Sadao Maou. At the same time, Sadao's high school-aged coworker Chiho Sasaki pursues a new dream with hopes to protect not only herself but also her friends. Secretly training with Emi and Suzuno Kamazuki to develop telepathic powers, Chiho's training is cut short when a group of demons abducts her. As angel and demon attacks threaten the fragile peace between the two worlds, Sadao and Emi need to put their troubled past behind them if they want to have a chance to find their new purpose in life.

While walking through the forest one day, a witch named Alyssa finds a bush glowing with a magical aura. She discovers a baby who, although not a witch, possesses magic that is too strong for that of a mere human. As such, Alyssa decides to raise the child as her own, naming her Viola. Sixteen years later, Viola is all grown up and now towers over her youthful mother, and her mature looks cause many to confuse their ages. Nevertheless, Alyssa adores her child despite Viola's possessive streak and tendency to drive away anyone she fears will take away her mother's love. Viola may not be sure where she came from, though she has all she needs in Alyssa and the plethora of Alyssa's friends who have come together to raise her. Under Alyssa's guidance, Viola will learn to master her magic and make her adoptive mother proud.