Office worker Min Joon (Chae Jong Hyeok) lives a monotonous life, spending his days going to work at his 9-to-5 job and going home. Despite societal pressure to achieve more as he progresses through his 30s, Min Joon feels stuck and unfulfilled. However, his life gets a shake-up when his workplace gets a new employee that just so happens to be Jin Hwan (Sung Seung Ha), his ex-boyfriend from 10 years ago. Compared to Min Joon, Jin Hwan is confident and charismatic, easily charming his new co-workers, reminding Min Joon of just how different they are. While Min Joon initially attempts to keep their past relationship outside of work, Jin Hwan seems to have other plans. Will things go differently for them this time, or is the past best left behind? This drama was adapted from the web novel "Eul's Love" by Moscareto.