Movie 2: The Castle Beyond the Looking Glass

Inuyasha and company start out battling Naraku.  Then each person  goes their separate ways: Sango going to find her younger brother Kohaku, Miroku goes back to his old home, and Inuyasha, Kagome and Shippo go to find the rest of the Shikon shards.
Unfortunately this peaceful interlude doesn't last. Shortly afterward, the full moon rises, and just keeps rising each night bringing with it the promise of danger. Kagura and Kanna go in search of a mirror, where, locked inside, is the ruler of the eternal night, Kaguya. To set her free they must gather five items and drop them into the five lakes of Fuji. Setting her free means danger for Inuyasha and the others, who are forced to face this new threat.