Some kids sneak into Adashino's store house and find an ink stone.  They play with it but soon fall ill with the strange symptom of lowered body temperature.  Ginko comes to help and discovers that the ink stone was formed from an old mushi that was once like a nimbus cloud.  It has solidified into a rock that was formed into an ink stone.  When mixed with water and rubbed it is freed just a little.  Now Ginko must find a cure for the kids and admonishes Adashino for collecting things that are potentially harmful to them.