Hiroki Fujisawa and Takuya Shirakawa have two things in their lives that they admire: their classmate Sayumi Sawatari and the towering Ezo Tower across the Tsugaru Strait. Driven by curiosity about the structure beyond their reach, they build an aeroplane from a fallen drone named Bella Ciela to fulfill their dream of reaching the top of the tower. Later joined by the girl they love, Hiroki and Takuya promise Sayumi to fly with her to the top together. However, Japan is divided into two parts due to conflict near the base of the tower, which marks the border between America-controlled Southern islands and Soviet Union-occupied Northern lands. Tragically, Sayumi disappears, and Hiroki and Takuya never see her again. Unbeknownst to them, she suffers from a sleeping disorder that leaves her comatose for three years. Although they later learn about Sayumi's condition, they discover an odd connection between her unconscious state and the same tower they had planned to conquer together.
The film won the Best Animation Film award at the Mainichi Film Awards in 2004.