Ginko is on another adventure as he is brought to a very peculiar island, by a young boy Nagi. Ginko is taken to see a girl, who the island inhabitants refer to as "Ikigami" and is said to be able to perform miracles however Ginko discovers that there is more to this.

On a rainy day Ginko takes a rest from his travels and comes across a man named Kourou who seems to be obsessed with a rainbow. To pass the time Kourou reminisces in his past, with the events which led to him pursuing rainbows whenever they appear. Ginko explains to him that the rainbow which he is searching for is actually a Mushi known as "Koda" but there seems to be more to it.

"Don't let yourself be blinded by fear and anger. Everything is only as it is..."

A boy named Yoki, who's able to see Mushi, was found in the woods by some mysterious lady named Nui with only one eye. It turns out that Yoki was travelling with his mother when a mudslide crushed his mother and he was left all on his own. Yoki's leg later heals itself however he doesn't seem to have anywhere to go so he stays with the Nui and begins to learn some things about the Mushi known as "Tokoyami".

It is spring, and Ginko is taking a boat through a river, when the boat's boy, Kaji, asks Ginko whether he could help his mother, who's forgetting things and can't sleep. At first glance it may appear to be progressive amnesia, however something isn't right.

"All that is in my world... is seem sound taste and touch. That is all. That is enough..."

Finally able to reach a city, Ginko comes across a "biwa hoshi" named Amane, singing songs about Mushi and she is immediately able tell that he is a Mushi-shi. So she forces him to stay a night at an inn when she later reveals that she once saw a "Ganpuku" a very rare Mushi that will make the host see better and better until they die.