June 23rd, 2008. That is the day when all started. The day when a huge accident occured in a NamYoung subway station. The day when Ma-rin and So-jun first met and fought, which saved their lives. And the day when So-jun lost his parents. That is where and when all started. In NamYoung station and on June 23rd, So-jun became a time traveler without him knowing why. Peeking into more of his future to come, he keeps seeing this woman, Ma-rin. Not knowing that she is also a surviver like him, he feels the need to stay with her.