 On January 1, 1983, high school teacher Ji-hwan (Jo Jeong-seok) meets a robber and loses consciousness while proposing to his fellow schoolmate and lover Yoon-jung (Im Soo-jung).On January 1, 2015, violent detective Gun-woo (Lee Jin-wook) will also be shot and killed by the criminal he was chasing.About 30 years apart, Ji-hwan and Geon-woo, who were taken to the same hospital at the same time and at the same time, manage to survive from life-and-death situations, and after that day, the two begin to see each other's daily lives through their dreams.