In the turbulent 1940s and 1950s, love was definitely hard to come by - an engagement token, a love song, or a promise was enough to make lovers dream about it. Policeman Fang Daolong (played by Andy Lau) with a complicated identity meets a legendary woman, Chen Yuerong (played by Tang Wei). Their love story spans three cities: they fell in love in Anhui, separated in Shanghai, and still adhered to a promise to each other - waiting to reunite in Hong Kong. That night, Fang Daolong waited for the boat to pick up Yuerong to dock on the shore of Hong Kong Island, but unexpectedly, the boat had an accident. Will Yuerong finally arrive in Hong Kong smoothly and start a new life with Daolong? The film is based on a true story and tells a love story of a father's generation.