Kang San Hyuk is a fearless and intelligent emergency service worker. He excels as part of his rescue team, responding to 119 emergency calls – and often saving lives in the process. But he is blighted by memory issues, and cannot remember key details about his childhood. He longs to unlock the secrets of his past. Meanwhile, Jung Yeong Jae is a passionate young surgeon whose new residency sees her posted to a mysterious forest. When his latest daring rescue mission also sees Kang San Hyuk enter the forest, he meets Jung Yeong Jae – and the pair feels strangely drawn to one another. Little by little, they realize that they share a once-forgotten secret. And the longer they spend in the seemingly magical forest, the closer they get to discovering the truth about their pasts – and the key role the forest plays in their intertwined destinies…