A teenager discovers that he is an Ajin and flees before the authorities experiment on him. Other Ajin plan to fight back and he must choose a side.

Takao, who is training to become a shoemaker, skipped school and is sketching shoes in a Japanese-style garden. He meets a mysterious woman, Yukino, who is older than him. Then, without arranging the times, the two start to see each other again and again, but only on rainy days. They deepen their relationship and open up to each other. But the end of the rainy season soon approaches …