Lin Xichi (Song Yiren) grew up in a broken family. The absence of her mother made her lose confidence in love a long time ago. Xu Fang (Zhang Yao) is Lin Xichi's childhood playmate. He witnessed his friend growing up day by day, experiencing the heartbreak and ups and downs that are indispensable in life. Although his heart is full of love, he can't do anything. All Xu Fang can do is hide the surging feelings for Lin Xichi in his heart, turn into a silent but eternal sea, and silently guard Lin Xichi. Fearing that she would be hurt, Lin Xichi shut down her love nerves. Although Xu Fang would always accompany her, for her, Xu Fang would always be the harmless big brother. When one day, Lin Xichi suddenly realized Xu Fang's feelings for her, could she face her own heart in panic?