耿耿(何蓝逗 饰)是一名技艺十分精湛的女摄影师,在学生时代,她有过一段无疾而终的青涩恋情,这段恋情至今依然深深的影响着耿耿。时间转回数年前,彼时的耿耿还是身穿校服的懵懂少女,在老师的安排下,她和学校里成绩最好的帅气男孩余淮(陈飞宇 饰)成为了同桌,他们一个是学渣,一个是学霸,互补的性格令两人之间很快就碰撞出了火花。 随着时间的推移,耿耿和余淮的感情从最初的友情一步一步的成长,两人许下了美好的约定,约好了考入同一所城市的同一间大学。然而,在约定之日的那一天到来之时,余淮竟然人间蒸发了,从此音信全无。Geng Geng had been an ordinary girl before her entry to the best high school in the province by chance. She doesn't like her life there until she meets Yu Huai, her seatmate - their names make up word "Geng geng yu huai", meaning "Unforgettable memories".