My idea for a start:

The young mage apprentice Gustavo faces a challenge. He lived inside the college and walked across one of the empty hallways. But there he encounters a beast of old legends: A frost troll. Why? Who left it stroll freely across the campus? No matter; It is aggressive and he will need to defeat it. The problem: he is a specialized ice mage and trolls are resistant to frost.

You can go in a different direction using the heading if you want.