mu chenghe, a phd student in the department of physics at donghu university, misunderstood the exam for xue tong, a junior student in the department of english, during a temporary invigilator for the final period. bbb。 from then on, the two formed an "indissoluble bond". during the interaction between you and me, mu chenghe and xue tong fell in love with each other and started a romantic love story of two-way secret love. during college, xue tong met three dormitory friends: the cold and beautiful zhao xiaotang, the lively and enthusiastic bai lin, and the quiet and gentle song qiqi. the four girls with different personalities also experienced various love stories while gaining friendship. from school to society, from family to work, despite the joys and sorrows, the four girls each have their own growth and gains. some people leave forever, and some things come to an end. good friends and lovers are still around, and the days of the past have become an eternal exclusive memory.