The usually bright teacher Xiao Shui Guang (Sierra Li) becomes depressed after losing her boyfriend. Because of an incident at school, she gets to know the older brother of one of the students Zhang Zheng Lan (Jiang Chao), who is the boss of a games company. Zheng Lan discovers that Shui Guang is the one who once gave him the idea for a game and starts to pursue her. He soon realizes that she closed herself off and thus promises her: “You protect your secret and I will protect you.”
