Cait's companion quest.
1. Cait's sister Calla is still missing after being thrown through a portal between worlds. You've never even heard of magic like that before. Taking Cait to find a knowledgeable sage or scholar might answer a few questions.
2. It didn't take much coaxing to get Cait to join up with you, and the perky cat-girl's presented you with a lead: apparently there's a witch in the woods, Lady Evergreen, who lives beyond the old stone bridge. Evergreen may know something about the portal in the ruins, and if so, could shed some light on what happened to Calla that night.