When two souls find one another, nothing can tear them apart. Widower Takumi lives a quiet life with his six-year-old son Yuji after the loss of wife and mother Mio. 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.

A 'Gaiden' edition of the Japanese horror found footage series "Not Found".

Along with his young son, Ji-ho, Woo-jin misses his wife Soo-a, who died after promising to return a year later with the rainy season. Miraculously, they reunite with Soo-a when the rainy season comes around, but she has no memory of her husband and son whom she dearly loved.

Drained from her life in the city, a young cellist moves to a quiet small town, where she encounters an old friend who helps her heal and remake herself.