Two OVA episodes featuring additional stories. Episode 0: Ritsu and Takano used to date back in high school, but broke up due to a misunderstanding. This is that story. Episode 12.5: Hatori and Chiaki go to visit the latter's family. It's really awkward in many, many ways.

Yearning to make friends and perform live with a band, lonely and socially anxious Hitori "Bocchi" Gotou devotes her time to playing the guitar. On a fateful day, Bocchi meets the outgoing drummer Nijika Ijichi, who invites her to join Kessoku Band when their guitarist, Ikuyo Kita, flees before their first show. Soon after, Bocchi meets her final bandmate—the cool bassist Ryou Yamada. Although their first performance together is subpar, the girls feel empowered by their shared love for music, and they are soon rejoined by Kita. Finding happiness in performing, Bocchi and her bandmates put their hearts into improving as musicians while making the most of their fleeting high school days.

Luo Xiaohei is a young monster who normally takes the form of a small black cat. Living freely in the forests, gradual deforestation and human development force him to flee and find a new home. Wandering the city streets, the black cat struggles to survive until he encounters Feng Xi, a fellow monster who takes Xiaohei to an isolated island inhabited by a small group of monsters. Excited to find what he thinks is his new home, Xiaohei lives with the monsters for only a short time before Wuxian, a human Guild Executor, arrives on the island in pursuit of Feng Xi. Feng Xi and his companions manage to teleport off the island, leaving Xiaohei and Wuxian alone. Though Xiaohei refuses to cooperate with the man who attacked his friends, Wuxian forces the black cat to travel to the Guild along with him. Embarking on an uncertain journey, Xiaohei is exposed to a new perspective on the relations between humans and monsters in a rapidly changing world.

Yoichi Isagi was mere moments away from scoring a goal that would have sent his high school soccer team to the nationals, but a split-second decision to pass the ball to his teammate cost him that reality. Bitter, confused, and disappointed, Isagi wonders if the outcome would have been different had he not made the pass. When the young striker returns home, an invitation from the Japan Football Union awaits him. Through an arbitrary and biased decision-making process, Isagi is one of three hundred U-18 strikers selected for a controversial project named Blue Lock. The project's ultimate goal is to turn one of the selected players into the star striker for the Japanese national team. To find the best participant, each diamond in the rough must compete against others through a series of solo and team competitions to rise to the top. Putting aside his ethical objections to the project, Isagi feels compelled to fight his way to the top, even if it means ruthlessly crushing the dreams of 299 aspiring young strikers.