"Why do you challenge me when you can't even win?" Nam Soha, an assistant in the planning team, and Yeon Min, an assistant in the design team, have been like enemies ever since a trivial incident at their welcome party, despite being colleagues. One day, Soha helps Yeon Min, who has just moved in next door, and as a reward, they end up drinking too much with the lunch Yeon Min brought, causing them to fall asleep in the same bed. When Yeon Min wakes up, he is startled to find himself in Soha's arms and runs away, trying to avoid Soha, but Soha, feeling a sense of challenge from Yeon Min's reaction, keeps approaching him. Meanwhile, the two end up tangled together in Soha's car during an off-site work outing... Soha and Yeon Min, who were once the best of enemies. Can hatred turn into love, and can love grow from that?