A German Captain and an American Captain help each other survive the North African desert during WWII. They meet again a year later during combat operations in France.

Having lost his colleague who was also his brother-in-law to a serial murderer two years ago, homicide detective Jae Hwan is unable to contain his hatred toward the murderer and dives headfirst into hunting the brutal killer. Jae Hwan finally comes face to face with the murderer Jin Hyuk but in the heat of the chase, they get into an accident. Waking up in a hospital, Jae Hwan realizes his body has been switched with that of the murderer. To protect his family and uncover the secret of this body switch, Jae Hwan begins a desperate chase.

While the Second World War rages, the teenage Mahito, haunted by his mother’s tragic death, is relocated from Tokyo to the serene rural home of his new stepmother Natsuko, a woman who bears a striking resemblance to the boy’s mother. As he tries to adjust, this strange new world grows even stranger following the appearance of a persistent gray heron, who perplexes and bedevils Mahito, dubbing him the “long-awaited one.”