Before Mio dies, she draws her son a book. In it, she promises him to come back during the rainy season six years after her death, to spend some time with him. He was waiting eagerly and when the rainy season finally arrives, she really appears! She doesn't remember where she is from, who she is or where she is. She also doesn't recognize her own son. But the tiny boy is sure that it's his mother and brings her home. Takumi on the other side, doesn't know why there is another person who looks like his dead wife and tries to think everything through, while he takes care of both of them.