Synopsis: Three years ago, Min-woo (Song Seung Heon) accidentally lost his beloved fiancee. He chose to study abroad with grief. At that time, Shen Hye-won (Son Ye Jin) was a quiet girl with congenital heart disease. She could only sit in the corner while watching others jump healthily.Three years later, Hye-won, who had previously received a heart transplant, became lively and cheerful, and had a beloved boyfriend. At the airport, Hye-won passed Min-woo who came back from abroad and felt the rapid beating of her heart. After returning to Korea, Min-woo went to the mountain where he had climbed with his fiancee, where he met Hye-won, who was lost. The two were trapped in the mountain and had communication...