Do you still remember those years in college? The most youthful and beautiful time. There you will meet Nie Jiaqi, a "lady" ghost who is gentle on the outside but full of clever ideas on the inside. There you will meet Qiao Zhengxi who is lively on the outside but mature and considerate like an uncle on the inside. There you will meet Mo Xiaoyu who is lively and bright on the outside but sentimental on the inside. There you will meet Ye Ran who is dull on the outside but smart and sensitive on the inside. . . . . How many four-dimensional spaces overlap to form you, me, his college years, the youthful and most beautiful years