"Hey! Go out with me, Cha Wonwoo." The lonely and tough days of being a 20 years old. The relationship between the two, which started with just a simple word, has more days of quarreling than having fun, "I've never been tired of living together for the past 10 years, but we can't live forever." After spending 10 years together, we became comfortable with each other like a family. The story of 'The Most Ordinary Relationship,' an unusual and common love story that's annoying but leaves you feel empty without it.