After a motorcycle accident, Kang Qiao is rushed to the hospital, where he is supported by his close friends Zhu Li and Zhao Yi who try to lift his spirits. Zhu Li, the hospital owner's daughter, secretly harbors feelings for him. One day, while looking out the hospital window, he spots a striking young woman and becomes entranced by her mystery, falling for her during his recovery. That same night, he witnesses the woman stabbing an old man, presumably her father. She and her mother drag the body away and bury it in an abandoned area near the hospital. Kang Qiao, swept up by his crush, chooses to stay quiet rather than intervene.
Soon after, a threatening note arrives, warning him to stop digging into the incident. He suspects someone is watching him, and that the mysterious woman may be in danger. He resolves to follow her, even trespassing into her home to seek clues. He is startled when he finds her in the shower and leaves. The next day, a call from a mysterious number cautions him not to stalk her, but he remains determined to protect her. Through these clues, he learns her name: Xia Yingying, a woman who works at a large company, and the mystery deepens.
To get closer, he becomes her client and they share a dinner. He offers to drive her home, but accidentally reveals that he knows where she lives. Xia Yingying grows wary, and Kang Qiao finally admits that he was spying on her during his hospital stay. Yet their tension softens into trust as they spend time together; she warns him that her family is strict and to tread carefully. After their day together, Kang Qiao is besieged by men sent by her mother; he is beaten badly but refuses to disclose Xia Yingying's whereabouts.
Back at the hospital, the place where Xia Yingying's father was buried is dug up. He rushes inside to find Xia Yingying, only to witness Zhu Li attempting to poison her with tainted water. Zhu Li proclaims her love for him and reveals she installed a camera in his hospital room; Zhao Yi confesses to being her accomplice, because he loves Zhu Li. Zhao Yi had dug up the supposed grave of Xia Yingying's father, but the only thing found is a pile of infant supplies. The police arrive and arrest Zhu Li. Xia Yingying is taken away by her mother, with Kang Qiao chasing after them on his motorcycle.
Moments of truth arrive when Xia Yingying finally opens up. She explains that the old man was not her father, but her husband, whom she married to help pay her mother's debts. She had become pregnant, but the infant died shortly after birth. A quarrel with her husband led to a heart attack as she prepared tea, and the moment was misread as a stabbing. She buried the infant's supplies near the hospital, a detail Kang Qiao had witnessed long ago. Ten years pass, and Xia Yingying contemplates leaving him, yet her husband’s business troubles entangle them and he develops cancer. She stays by him through chemotherapy and lawsuits, and after his death she leaves his side. She and Kang Qiao eventually reunite, and they look forward to spending another summer together.
