"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.

Ginko arrives at a secluded place, to meet an old acquaintance, who seems to be in charge of a large volume of archival, confidential text. Ginko is allowed to read it, and discovers it is the work of Tan'yu, a writer. Tan'yu is the descendant of the Karibusa family, being born with a black mark on a part of their body.

In a cold mountainous region, Ginko is wandering around the snow cover plain when he hears a sound ringing through the cold air and he also notices some rust on a tree. Ginko enters a nearby town to find the rust covering everywhere, including the people. The village chief tells Ginko that this is a sickness that has been affecting the town for 14 years that the people have been slowly losing the movements of the limbs and it's said that a girl called Shige is the cause of it.