The place promised in our early days (2004 anime)

The place promised in our early days is beautiful. as in visuals. 

 

mainly the story is that hiroki promised Sayuri to fly her to the tower.

 

Sayuri was sick and goes into coma.

Sayuri appears to have been in a parallel world but she manage to invite Hiroki into it as well.

hiroki again promised to Sayuri to bring her to the tower.

 

finally hiroki really managed to bring Sayuri to the tower and it really heals her and she lost most of the memories but life will go on.

 

hiroki destroys the tower.

 

again not much explanation about what is the purpose of the tower in details.