On his 20th birthday, Yun Tae-o gets his grandfather's house but soon finds that living by himself doesn't come with all the perks he had imagined.

Han Song-i, Seo Do-hyeon, Oh Ga-rin and Choe Hun all end up going to Tae-o's place but he's not home; Tae-o gets alarming news about Song-i.

Without knowing how it happened, Tae-o gets stuck having housemates and learns more bad news about Song-i when he goes home for dinner with his family.

Tae-o contemplates what he overheard and is convinced he knows what it means; to show her appreciation, Ga-rin throws a party, which Do-hyeon attends.

Tae-o keeps misreading Song-i, exacerbating the confusion between them; Do-hyeon wants to know more about Song-i's relationship with Tae-o.

Tae-o makes a breakthrough with Ryu Se-hyeon but is shocked when he sees her house; Do-hyeon and Song-i try to figure out where they stand.