Kang Seulgi and Bae Joohyun have been best friends for as long as they can remember. They always understood each other without needing many words. But when Joohyun returns to Korea, heartbroken after a tough breakup, she asks Seulgi to join her for drinks. What starts as a night of comforting words soon takes a turn when the alcohol flows more freely, and the night stretches longer than either of them expected. The next day, everything between them feels strange. There's an awkwardness neither of them can ignore. Joohyun then finds out she's pregnant because of what happened between them that night. When Joohyun's grandfather learns about that, he makes them get married, putting both Seulgi and Joohyun in a situation they never wanted.