Widower Takumi (Shidou Nakamura) lives a quiet life with his six-year-old son Yuji (Akashi Takei) after the loss of wife and mother Mio (Yuko Takeuchi). Yuji unfailingly remembers her promise to him: 'I'll be with you again in a year's time, when the rains come.' On the first anniversary of her passing, Takumi and Yuji are taking a walk in the woods when they come across a woman sheltering from a monsoon downpour. She bears an uncanny resemblance to Mio, but has no recollection of who she is or what she is doing there. Family life resumes from where they left off, but they must say goodbye once more in six weeks time'