At the request of Tanyuu Karibusa, Ginko triggers to investigate a phenomenon that might be related to a hazardous mushi, much to the chagrin of Kumado Minai, the present head of a long line of mushishi, who's in charge of the area. As Ginko and also Kumado get to the bottom of the Path of Thorns, the secret of the Minai line of mushishi is exposed.