Place Dawn's Gambit in the Viewing Room of the Scholomance. Defeat Vectus, then return to Betina Bigglezink.
I've placed Dawn's Gambit in the container you brought to us, the one that held the dragon eggs. Your job is to bring it deep within the Scholomance.
The undead mage Vectus leads a team of scourge scholars... place Dawn's Gambit in their chamber, called the "viewing room." It will then react with the undead found there and, with a little luck, destroy them!
After that, defeating Vectus shouldn't be a problem. Right?