From Storm in Heaven:

The first mouse appeared on the night of a full moon over two thousand years ago. A timeless children's song among the humans tells how it made powerful mice companions and legions of war mice. Then it declared war on all humankind. Pai'yan is on of the king's honored 7 heroes, renowned for his skill in fighting the mice. He comes home after a long campaign to find his young son kidnapped by the Magic Mouse, and his son's pet kitten Toraji transformed into a half-human cat mix. Now Pai'yan travels with Toraji, searching for any word that could lead them to the Magic Mouse and his missing son.