A young boy named Mahito yearning for his mother ventures into a world shared by the living and the dead. There, death comes to an end, and life finds a new beginning.

After losing his mother, Mahito moves to the country with his father and new stepmother, Natsuko, and encounters a mysterious gray heron.

When Natsuko suddenly goes missing, Mahito, guided by the heron, must find her by venturing into a dream-like realm where the living and the dead exist side by side.