'Fill in the Blank' is based on the hypothetical psychological theory that the highly materialized life of modern people can be explained with 9 objects in any case. It is a documentary that contains the journey of four K-Pop idols - Oh My Girl's Hyojung, The Boyz's Q, ATEEZ's Wooyoung, and LESSERAFIM's Kim Chaewon - to find nine objects that express and explain themselves.
Sul Won is an out-of-work young man whose mother runs a low-cost boarding house for students and men who don’t have enough money to buy or rent an apartment on their own. But when his mother suddenly has to up sticks to return to her provincial hometown, she leaves Sul Won in charge of the boarding house – becoming the de facto live-in landlord. The residents of the boarding house are a mixed bunch. They include a high school senior, who also happens to be Sul Won’s cousin. There is also Sul Won’s former college friend, as well as Kim Chun Seo, a high school teacher. Rounding out the number is a third-year Art student who dreams of becoming a cartoon author. As the young men spend more time together, a close bond of friendship begins to form in the house. But when Sul Won discovers that some of the tenants have begun to develop a crush on him, Cupid could well come calling!
Smart, clever, and resourceful, Daon worked hard to overcome being poor. But his cheap ways are getting on the last nerve of his coworker, Sunghyeon, who hates him! After an incident with his own impoverished parents, Daon is suddenly growing closer to Sunghyeon while balancing feelings for his former tutor, Jaemin. With mixed emotions and unspoken secrets, will Daon be rich with love or fall back into poverty?