우연한 기회로 올드카의 모습을 한 타임머신을 얻게 된 해준. 그리고 예상치 못한 엄마의 죽음을 맞게 된 윤영. 1987년으로 타임워프를 하던 해준은 의도치 않게 윤영을 치는 교통사고를 내버리고. 둘은 어쩌다보니, 함께 1987년으로 떨어져버린다.
If Hae-jun hadn't been curious, he wouldn't have stumbled upon a time machine. With a few button presses, he quickly figures out how to use it, and that marks the beginning of his journey as a time traveler. Yoon-young is occupied with her job as an editor for a renowned writer, leaving her little time to spend with her mother. Then, suddenly and unexpectedly, tragedy strikes as Yoon-young receives a call that her mother has been found dead.