During the freshman military training shooting range, the exhausted freshman YOYO (played by Lin Yuan) accidentally shot a male classmate Qi Jun (played by Xue Zhiqian) under mental stress. Qi Jun, whose life was hanging by a thread, was saved by a Labrador puppy that stepped forward. The sunny and handsome Qi Jun became the boyfriend of the beautiful and quirky girl YOYO because of this opportunity. Not only that, this magical puppy also made Qi Jun, YOYO, Youzi (played by Jiang Luxia), Kesai (played by Deng Zifei), Brother T (played by Zhao Yinglong) and Daxiong (played by Qian Zhijun) become close friends. They named the puppy "Sunny", and Sunny has since become their common good friend. They started their college life with infinite longing, vowing to fulfill their respective dreams within these four years! College time passed in a flash, and just before graduation from their senior year, Sunny, who had accompanied them through their youth, was lost. Several people decided to abandon everything to find Sunny. What they are about to face is not only the lost Sunny but also a journey of searching where ideals, love and reality collide.