Callie immediately noticed how the atmosphere around them seemed to have changed. She felt it. This structure was....calling to her? She could almost hear a voice saying that they only open at her wish. 

...What?

A loud click echoed and the Will O' the Wisp was bouncing excitedly. There was this feeling that she was about to step into something unknown. That her life was going to change drastically once she stepped through. She watched as Merrill opened the door and stepped through, and he mentioned that only she could have opened the door with an unseen key. 

This was definitely screaming magic now. Callie was ready to bolt if she needed to. But for now, she stepped through the door, and into the small cramped compartment, where two figures sat. She raised an eyebrow at his words. She didn't like this. But she needed to stay calm. She can't afford having her magic surge...and yet, it seemed like this guy already knew that she had magic. 

When he asked if she was ready, she answered skeptically, "No, but it doesn't look like I have a choice, do I?"