With Inuyasha incapacitated by a full moon, Miroku and Sango try to track down the woman stealing bones.; Kanna presses her attacks on Inuyasha through the mirror demon, oblivious to the damage she continues to suffer.; Kanna destroys herself in an attempt to take Kagome and Inuyasha to the underworld. But as she dies, a shard of her lands in Kagome's eye and warns Kagome of Naraku's fatal weakness.; The gang encounter a village where a demon has been prowling at night, removing the skeletons from living beings and leaving a pile of dead skin and organs behind.; The Bone Demon decides that Sango's boomerang bone will restore it to health and he'll do anything to get it.; With Miroku unconscious and easy prey, Sango sacrifices her boomerang bone in order to destroy the Bone Demon before it can harm Miroku.; Seeking to repair the boomerang bone, Inuyasha and the gang visit The Master of Potions. The sage agrees to fix it, but only if Sango can defeat a horde of demons by herself.; Sango faces the angry souls of her boomerang bone. The Master of Potions offers a potential cure to Miroku's spreading poison.; Miroku's potion won't cure the poison, only deaden the pain from it. The souls of the boomerang bone demand that Sango choose them or Miroku.; Sango and Miroku triumph over their adversities through their dedication to each other. Sesshomaru is offered the key to completing Tenseiga's growth by a mysterious stranger.