The film tells a story of 2 girls who were born on the same day and unintentionally switched at birth. Their lives are completed changed due to the misplacement when they are returned to their respective families.

The film spans two decades, as the story unfolds in a series of flashbacks that begin when Qiyue and Ansheng were just thirteen. The two became inseparable, until they met a boy who ended up tearing their lives apart.