The drama tells the story of a man and a woman who have been separated forever by death, transcending the limitations of time and space and miraculously meeting again. In the drama, Kim Hee Sun will play Yoon Tae-yi, a genius physicist who holds the key to uncovering the secret of time travel. She meets and works together with detective Park Jin-kyum, played by Zhou Yuan, to face difficulties. In the process of unraveling the secret of time travel, they gradually understand the secret hidden in themselves. Kim Hee Sun will play Yoon Tae-yi, a genius physicist who holds the key to uncovering the secret of time travel. Zhou Yuan plays detective Park Jin-kyum, who observes objectively no matter what the incident is, and investigates only with evidence and logic, which is recognized by his colleagues. He is shocked when he learns that there are time travelers in South Korea.