Love the magical, mysterious sort of feel. I could just see the person’s face (still unsure if our protagonist is a guy or a girl) as they hesitantly turned the key. Very fun.
Okay, now is as good a time as any for me to confess my undying love of all things related to secret passageways. Especially ones where you least expect them. Someday I’m going to build a house with more secret passageways than regular doors.