Childhood friends Han Jeong-woo and Choi Yi-seo have been friends for 25 years. Jeong-woo has had a crush on Yi-seo for a long time, but Yi-seo doesn't see Jeong-woo as rational at all. Then one day, the two begin living together due to a certain incident... "You, why are you so big?" "I told you, you're much bigger than those toys." Are they crossing a line that friends shouldn't cross?! "Put it in, put it in? I don't think it'll fit." "Our Yi-seo, it'll get all wet and fit in."