InuYasha the Movie 2: The Castle Beyond the Looking Glass

Synopsis

Inuyasha and company have finally destroyed Naraku. And each start to go in their separate ways. Sango going to find her younger brother Kohaku; Miroku back to his old home; Inuyasha, Kagome and Shippou go to gather the rest of the Shikon shards. Unfortunately this peace is not to last. Shortly afterwards 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 the worst danger for Inuyasha and the others. Who are forced to face this new threat.

(Source: Anime News Network)