During their middle school years, Mikumo and Sei were inseparable childhood friends, often mistaken for a couple due to their strong connection. However, their unbreakable bond came to an abrupt end when Mikumo had to move to China with her family. As a farewell gift, Sei gave her his hat, but the gesture went unnoticed by Mikumo. After several years, Mikumo returned to Japan and reunited with Sei during their high school days. Is it possible for their former spark to reignite?