After his father unexpectedly has a flash marriage with a female CEO, the teenager Xu Xing moves into their spacious flat with her three sisters to start a co-renting life. The cold and strong second sister of the company, the gentle-natured third sister studying psychology, and the lively and carefree campus belle aunt enter Xu Xing's daily life. On one side are campus studies, club parties, and entanglements among classmates; on the other side are comical co-renting routines under the same roof. The hidden identity of online dating and the budding affections between the teenagers unfold amidst laughter and small conflicts in daily life, leading Xu Xing to experience growth step by step in the lively new life and reap his own life story.