Living in Florence, Italy, Junsei Agata is studying to be a restoration expert who specializes in fine art. He feels life is empty. He was clinging to the memory of one girl with whom he spent his school days. Her name was Aoi. One day, he learns Aoi is in Milan and finds she lives with a wealthy American businessman. He finds she lives in a different world and runs away to Japan.
Junsei remembers a 10-year promise. When he was a college student in Japan, he made a promise with Aoi to meet on the top of the Duomo in Florence on her 30th birthday. He hangs on to one slight hope that Aoi must have remembered the promise. He decides to return to Florence to prove the love between him and Aoi is true.