The enemy meets at work, not on a single-log bridge. Cha Na-rae and Lee Sang-shik, who hate each other, were living next door to the company, not enough! Na-rae and Sang-shik were more thorough drawing lines than the 38th Parallel. Something happens to those who cross the line... Meanwhile, Kang-mi is embarrassed when her dream kiss partner appeared before her eyes last night. A newbie suddenly joins the Marketing Department 3 — "Baek Ma-tan". But this newbie, is he... "new"?