Hiroki Fujisawa and Takuya Shirakawa harbor admiration for two things in their life: their classmate Sayuri Sawatari and the vast Ezo Tower that stands boundlessly across the Tsugaru Strait. Fascinated by the limitless structure beyond their reach, Hiroki and Takuya begin constructing an aeroplane from a fallen drone they discovered—naming it the Bella Ciela—to fulfill their dream of one day reaching the sky-scraping top of the tower. Later joined by the girl they love, Hiroki and Takuya promise Sayuri to fly with her to the seemingly otherworldly top together. However, Japan has suffered a North-South partitioning that has fueled conflict near the base of the tower, which marks the border between the America-controlled Southern islands and the Northern lands occupied by the Soviet Union. Further along, Sayuri suddenly disappears, and Hiroki and Takuya never see her again. Unbeknownst to them, she fell victim to a sleeping disorder that left her comatose for the past three years. Although Hiroki and Takuya later learn about Sayuri's condition, they also discover that the girl's unconscious state is oddly linked to the same tower the trio had promised to conquer together.

To the shy and reclusive Ryuuto Kashima, associating himself with his popular classmate Runa Shirakawa is nothing but a distant fantasy—or so he thought. After losing a bet with his friends and being coerced into confessing to Runa, Ryuuto's world is flipped upside down: instead of the cruel rejection he was expecting, Runa agrees to go out with him! But dating Runa proves to be overwhelming for Ryuuto, who requests that their relationship remain a secret known only by their closest friends. His decision, however, leads to a series of mishaps that he fears will doom the relationship. As they work through their misunderstandings, Ryuuto reveals his insecurities stemming from his past experiences, and the two grow closer together. Just when things are getting back on track, Ryuuto's middle school crush, Maria Kurose, transfers to his class and begins to stir up a fuss. At the same time, terrible rumors about Runa spread around the school, prompting Ryuuto to take desperate measures to protect her.

One day, manga author Shin Karino is greeted by four-year-old Kotarou Satou, his new next-door neighbor, who gifts him a box of tissues. In Karino's eyes, Kotarou is an odd kid: he speaks in an extremely formal manner, and he lives alone in his apartment—no parents or relatives in sight. But Kotarou neither seems to mind, nor wants to rely on people. Feeling sympathetic toward Kotarou's circumstances, Karino decides to follow Kotarou to a bathhouse in case something might happen to him and there he comes to understand the little boy is not so different from him. Little by little, Karino—along with the other residents of the apartment complex—grows fond of Kotarou and his antics. At the same time, Kotarou himself might have found something akin to a family in his unique neighbors.

Now accustomed to his life at Ooezo Agricultural High School, Yuugo Hachiken explores the deeper aspects of what school life really means. As Hachiken learns more about himself and earns the skills necessary for his everyday tasks, he is even offered the position of the Equestrian Club's vice-president. The new semester brings a variety of agricultural dilemmas and personal conflicts, but, nevertheless, Hachiken perseveres in order to discover his dream and continue working together with his friends.