Raindrops and Rainbows is the seventh episode of the anime series.
Hiding from the rain, Ginko meets Koro, a man who pursue rainbows. Koro explains that when he was young, his father would predict the rain and drift away and be gone for days, after which he has no memory of what he was doing. His father would explain that the day before Koro was born, he saw a rainbow coming from the ground and it was the most beautiful thing he ever saw. As he touched it, he started seeing it more often, but years later he got bedridden and could no longer go out. Koro decided to find that rainbow and show it to his father. Ginko explains that was a Kouda Mushi, and decides to the search with Koro, as he had only seen it once, but now wants to see its base rooted.
Ginko tells Koro he will be searching with him until August and that unlike normal rainbows, Kouda has reversed order of colors and can appear anywhere and not only when the sun is behind you. With that information and Koro learning to read the weather, they manage avoid chasing normal rainbows. After Koro reveals he is searching for the rainbow for five years, Ginko realizes he isn't doing it only to show it to his father. Koro explains that his name means "rainbow-man" and he and his father were mocked. They were carpenters who build bridges, but he isn't as talented as his brother and after receiving an injury, he couldn't continue working and one day just ran from home. He always find himself chasing after rainbows and wants to confirm what his father was saying is true.
One day, Koro hears a voice, telling him it will rain and he sees a rainbow forming, realizing its Kouda. They run towards it, but until they reach it, its gone. Spending the night around the location the Kouda was, Koro recalls how his father apologized for giving him this name, but explains he wanted to name him after the most beautiful thing he ever saw. His father wanted to give him a new name, but Koro told him he wants to become even better bridge builder than him, but later ran from home. Waking up in the morning, Koro sees Kouda behind Ginko and they run towards it. Reaching it, Koro comments its the most beautiful thing he had seen and attempts to touch it, but Ginko manages to pull him out. He explains its Nagaremono, possessing life and drifting with no purpose. Koro realizes his father was possessed and feels that finally seeing it, part of him is gone and he feels refreshed.
Time after that, Ginko explains he never saw Koro again, but heard of indestructible bridge being build across a famous rogue river.