"Swallow" depicts the story of Cha Eun-sook, who published a book titled "Jebi," which tells a story of the past during the military regime of Chun Doo-hwan in 1983, and her son, Lee Ho-yeon, who finds himself hidden in the book.
Sung-hyun returns after 3-years of studying abroad. All alone in a 14-day self-quarantine, he begins to watch the vlogs of Soo-jin, the woman he was dating before he left. Each wonders if they should reconnect.
Yoon-hye likes Da-joo more than just as a friend but denies her feelings for the sake of their friendship. After some events following Da-joo being introduced to a boy, Yoon-hye is not able to hide her emotions anymore.