In-woo, an adjunct professor teaching art history, participates in an isolation experiment involving a famous artist. Three people join this experiment: In-woo, who wants to win back his love; Jong-min, a chicken restaurant owner who wants to make a lot of money; and Geum-ran, who has chosen to isolate herself from the world. These three are isolated for two weeks in a space cut off from the world, without smartphones, and can only communicate with the outside through the messenger Ji-sun. Furthermore, the messages they can send are limited to just 20 words. The rule here is that the messenger Ji-sun must deliver the 20 words exactly as they are given. However, the 20 words they convey to each other are clumsy and rough. So, Ji-sun decides to interpret their true feelings by slightly altering the words. Ji-sun relays messages between the isolated individuals and those left outside, connecting their heartfelt love stories. Then one day, In-woo realizes a new emotion. Ji-sun, who listens to his story, empathizes, and helps him, has somehow entered his heart.