7 years of relationship, and living together, Min Chae and Woong couple who are in the late 20s. HyunSu and Ji Hyo couple, in the early 30s and have been together for 1 year. Woong was a popular swimming instructor before his injury, now he works as a contract. Min Chae struggles to prepare herself to get a job. They are in a relationship for quite a long time, but they can't really talk about marriage due to realistic issues. Meanwhile, Ji Hyo hopes to put marriage off due to her worries of losing things after marriage, though Hyun Su kept asked for it. At that time, a new girl, So Young, appears and shows her interest in Hyun Su. Which couple will overcome this challenge, and be the one who makes it to marriage?...