The Place Promised in Our Early Days S01

In an alternate timeline, Japan was divided after its defeat in World War II, with Hokkaido annexed by the Union while Honshu and the other southern islands were under the United States' rule. A mysterious giant tower was built in Hokkaido, clearly visible from Honshu. In the summer of 1996, three ninth-grade students vowed to one day build an airplane that would allow them to unravel the tower's mystery. However, their project was left unfinished after Sawatari Sayuri fell into a coma and was taken to Tokyo for treatment. Three years later, Hiroki Fujisawa discovers that Sayuri is still in a coma and asks Takakawa Shirakawa for help in finding a way to keep Sayuri alive. What they still don't know is that there is a connection between Sayuri's coma, the tower's secrets, and the world.