And since, despite the world's admitted tendency towards situations best left in the more dramatic varieties of literature, it wasn't literally a stereotypical gothic novel, Kanimir didn't expect anything in particular to happen. If nothing else, there were far more storms that happened to happen at night than there were potentially literature-worthy shenanigans. So it's completely reasonable for him to be curled up in his grand library, enjoying a book on magical theory.
There is a soft flare of light, and a petite girl in a red sundress appears a short distance away, stepping through a rectangular pane of glow that fades away as soon as she emerges.
She looks around in mounting confusion and alarm.
Kanimir looks at her for several seconds. "Hello. I believe you might be lost," he says.
"...Through a Door," she says. "But... it's..." She trails off, shaking her head slowly.
He murmurs several words under his breath, then purses his lips. "I'm afraid I'm unfamiliar with the meaning of "door" in this context."
"That doesn't clarify the matter for me. I suspect I lack significant underlying context which you are used to taking for granted."
"My home, in the state of Pennsylvania, in the country the United States of America, on the planet Earth, in the Milky Way galaxy, but I suspect that at least some of that shall be as opaque to you as your explanation of how you came here was to me."
"The Door was a person who could create portals that lead from one place to another. I went through an out-of-the-way one, and now I am here."
"When did this person live? I feel quite certain that nothing like this has happened since I acquired this residence."
"Probably he was dead before I came here. Do you know if this particular portal has been used since?"
"So it seems possible, if potentially unlikely, that it merely sat here dormant for all this time."
She frowns slightly, dissatisfied with this analysis but not sure how to voice her concerns.
"Or, alternately, I might be misreading things due to my unfamiliarity with the underlying paradigm."
"It's very, very strange that you haven't heard of the Door. Everyone's heard of the Door. I can't imagine how far away I must have gone to find someone who hasn't heard of the Door."