The story is set in the year 2050, in a place called Sky City Tokyo. The main character, Park, is a window cleaner. If you've ever experienced those street windshield washers that descend upon your car when you stop at a red light, you can imagine what Park does for a living. Except worse, because in Sky City Tokyo, the cars travel in mid-air! How does a window cleaner become a hero? Read and find out!