"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".