3년째 '공무원 시험 준비 중'이라는 동네 대표 백수 봉필은 오랫동안 옆집 친구 수진을 짝사랑해 왔지만, 마음을 쉽게 표현하지 못한다. 하지만 수진이 동네 훈남 약사 재현과 결혼을 앞두자, 봉필의 마음은 다급해진다. 결혼식을 일주일 앞둔 날, 봉필은 수진의 마음을 얻기 위해 신비한 맨홀의 도움을 받아 현재와 과거를 오간다. 하지만 시간 여행을 할 때마다 자신이 만든 작은 변화가 예상치 못한 방식으로 자신의 삶을 바꿨음을 깨닫는다. 봉필은 과연 수진의 마음을 얻고 부끄럽지 않은 삶을 살 수 있을까?
Everyone has a memory of an unrequited love. Most of the time, unrequited love ends in embarrassment. However, unrequited love isn't all that bad. It can be sweet, and it can make your heart flutter. There is a man who has been in love with a woman for a very long time. They aren't lovers nor are they just friends. After giving up his dream to become a track athlete, he couldn't go to college. He spent three years doing nothing and another three studying for the civil servant exam. Now, a week before her wedding, and he's in turmoil over the prospect of losing the woman he loves. He travels back and forth in time with the help of a mysterious manhole in order to gain the heart of the one he loves. However, each time he goes back in time and returns to the present, he realizes that the small changes he made changed his life in unexpected ways. How can he get the girl of his dreams and live a life that he's not ashamed of?