Xiang, a student retaking the college entrance exam, suddenly receives a phone call. The caller is Lan, his childhood friend and former neighbor. Lan says she's also a retaking student and wants to attend a winter lecture series, hoping to stay in Xiang's room for a while. Lan, whom he hasn't seen for years, still retains some of her former features, but her figure has undergone a striking transformation. Her full breasts make Xiang unable to believe that he used to tease her about her flat chest. Lan, dressed casually in loungewear, unabashedly displays her ample bosom, seducing Xiang. Thus begins their erotic, sweet, and slightly bittersweet sexual relationship!