Touya accepts a quest to go to an abandoned castle to investigate a deceased magician's research on Slime Beasts, but the girls are reluctant to aid Touya due to their concern that slimes dissolve clothing. At the castle, the group encounter numerous slimes and discover that the magician had created a slime capable of transforming into models of beautiful girls. After Touya saves the girls from being caught by the slimes, the girls decide to burn the castle down, destroying the magician's research...