An ancient marriage custom has been passed down in Yushan Village: a young woman who wishes to marry the man she loves must climb the mountain and obtain love water from a mountain spring. Once her beloved drinks it, they are bound by a lifelong vow. A Yuan, the heroine, spends three years repeatedly risking her life to obtain the love water, wholeheartedly devoted to Qi Zheng. However, he cruelly deceives and keeps putting her off. She eventually discovers that he has secretly registered his marriage with her best friend, A Li. When the three-year courtship period expires, A Yuan finally gives up on him. She meets Zhao Xun, a man who genuinely cares for her, and he drinks her love water. By the time Qi Zheng realizes his mistake and desperately tries to win her back, their old promise has already expired. A Yuan sets off toward the happiness and future she truly deserves.