Lin Jianing and Zhou Hao have been in love for five years and are about to talk about marriage. However, just before their parents meet, Lin Jianing suddenly learns that Zhou Hao actually has a three-year-old "biological younger sister" named An'an, a fact he has kept hidden for a full three years. Even more unusual is that when the paternity test proves An'an is indeed Zhou Hao's half-sibling, Zhou Hao not only fails to breathe a sigh of relief, but instead is the first to ask, "Who else has seen the report?" This makes Lin Jianing realize the truth is far from over.