Dong-soo who has tic orders that make him swear without knowing it, visits Ye-ri"s rooftop house twice a week to deliver daily necessities that"s his job. Ye-ri is always shut in her room after the death of her younger sibling. While communicating with the world only by publishing Internet novels, she is comforted by Dong-soo. Twice in a week. Dong-soo and Ye-ri start talking about the things they have never told anyone before. She talks about her younger sibling who wanted to see an ocean without water and Dong-soo decides to her grant her that wish...will they make it?