Protagonist Xi Ning is an introverted and quiet sculpture major student. During her study tour in New York, after getting drunk, she took the initiative to chat up the mysterious mixed-race male Bo Zhaoye. After their one-night fling, Xi Ning left 100 US dollars and left in a hurry. Xi Ning originally thought the two of them would just never meet again, but she reunited with Bo Zhaoye during the campus club recruitment. Bo Zhaoye pressed forward step by step to "collect a debt" from Xi Ning, proposing a "contract girlfriend". Xi Ning, in order to gather her mother's life-saving medical expenses, agreed.