Three years after the start of the Pacific War, the boy Mahito’s mother died in a fire in Tokyo, and a year later his father married her sister and sent his son to the family estate in the countryside. The head of the family works at a defense plant and is rarely at home, so the boy has to spend his days with his pregnant stepmother and surrounded by elderly servants; moreover, from the very first day, he is tormented by a suspicious gray heron. One day, a bird tells Mahito that it can take him to his mother and lures him into a mysterious tower surrounded by numerous local legends.