A brass, slightly tarnished pocket compass, the needle of which is completely irregular – it slowly rotates in a circle, no matter how you hold it.

Beneath the compass lies a twice-folded, yellowed piece of parchment with a single handwritten sentence in faded ink:

“Don’t look for a place. Look for the hour when the shadow points north.”

And at the very bottom of the compartment, something dull glitters: A flat, unusually heavy metal key without a bit, which instead has small, delicate notches on the sides – almost like the punched card of an old music box.

What do you think: Which lock does this key belong to, or what does it open?