The death of Sheena Totsuki's roommate is casually announced at the start of class, and the day carries on as usual. In an orphanage that raises children as soldiers, death is nothing new to the residents. With their home country embroiled in a war that has dragged on for too many years and shows no signs of stopping, the institution's children are sent off to die in battle every day. In contrast to the other orphans, Sheena is deeply disturbed by the ongoing conflict and wishes for it to end. On the night of her roommate's death, Sheena met a blood-covered girl who remained jubilant despite the condition she was in. The next day, the girl appears as a new student in Sheena's class and introduces herself as Mimi Kagari. Initially thought to be a school myth, Mimi is said to be the secret weapon of the orphanage—a girl who cannot die. Assigned as Sheena's new roommate, Mimi hopes to get along with her and get accustomed to school life. However, unsettled by Mimi's carefree attitude toward the war, Sheena struggles to accept the world they live in, all while their unusual friendship flourishes amid the bleak situation.

After an accident sent her family to their deaths in the ocean, Hinako Yaotose keeps returning to the thought of sinking forever into the sea herself. With Miko Yashiro as her only friend, Hinako manages to keep up a semi-happy facade, but whenever Miko leaves her side, she slips into despair. Everything changes one summer when she meets a mysterious girl with eyes as deep and clear as the sea, drawing Hinako in like nothing else has in a long time. During her absent-minded search for the girl, Hinako is suddenly pulled underwater by a beastly deep-sea creature, only to awaken to the presence of the girl—Shiori Oumi—who takes on a monstrous form and kills Hinako's attacker. Despite this heroic act, Shiori's intentions are no different from any other monster's: she wants to eat Hinako. The following morning, Shiori walks into Hinako's class as a transfer student, and Hinako cannot help but smile—at last, someone who could fulfill her quiet wish for death has appeared before her.

Jun Shirasaki and the Jinguuji sisters are childhood friends and neighbors. When Jun's first girlfriend, the older sister Rumi, breaks up with him, she says something that complicates the three people's relationship, their first loves, and their romance—? (Source: MAL News)

In a world of constant war between humans and witches, there exist the beastfallen—cursed humans born with the appearance and strength of an animal. Their physical prowess and bestial nature cause them to be feared and shunned by both humans and witches. As a result, many beastfallen become sellswords, making their living through hunting witches. Despite the enmity between the races, a lighthearted witch named Zero enlists a beastfallen whom she refers to as Mercenary to act as her protector. He travels with Zero and Albus, a young magician, on their search for the Grimoire of Zero: a powerful spell book that could be extremely dangerous in the wrong hands. During their journey, his inner kindness is revealed as he starts to show compassion and sympathy towards humans and witches alike, and the unlikely companions grow together.