A Single Swallow is the story of a young woman Ah Yan. Ah Yan's life story, her journey from a naive young girl to a courageous young woman, is told from the perspectives of the three men in her life. After Japan's surrender, bringing an end to World War 2. The three men, after a day of joyous celebrations, take a vow to meet every year at the village. It was where they have lived, fought a war, and survived challenging times. Now seventy years later, they get to fulfill their promise. The American missionary Pastor Billy, the gunner’s mate Ian Ferguson, and a local soldier Liu Zhaohu come together…