Tessa (Josephine Langford) is a girl who has always followed the rules. In the eyes of her parents, she is an obedient and well-behaved daughter. In the eyes of her boyfriend, she is a considerate and sensible girlfriend. In the eyes of her teacher, she is a good student who abides by the rules and is polite. After she entered the university campus, such a girl met a boy named Harding (Hero Fiennes Tiffin). Harding is different from all the boys Tessa has ever seen. He has a rebellious look, a fancy and exaggerated appearance, and he has always been unconventional in doing things. Tessa's first impression of Harding was not good, but as time went on, some of his unique temperament gradually attracted Tessa, and she began to desire to be a free person like him. In a strange combination of circumstances, Tessa and Harding kissed, and then Harding's erratic attitude made Tessa more obsessed with him.