He feels an open summons and lets it grab him -
The summoner looks at Cam, looks at the circle, and then says, ".... Thaaaaat is not a teleportation spell."
"Okay," he says. "This I gotta hear."
He goes to inspect the circle. It's got strange foreign runes, rather than anything Cam has seen before. It's carefully, carefully carved, and obsessively exact, but absolutely incomprehensible.
"Also I am extremely sorry but I've got no idea how to put you back. Um. Like, really, really sorry."
"I have no idea how you got me either. This doesn't look even slightly like a summoning circle. Like, not even a bad one. I'm hoping you can send me back the usual way, because otherwise I will be sort of inconvenienced. How did I manage to miss someone making any remotely promising inroads on teleportation?"
"... Usual way? There's a usual way? Wait, are there ways to summon people to places? That's - not quite what I was aiming for, but hey, magic, I will take it!"
"...Do you live under a rock or are you also working on time travel or what?"
"Um. No to both? Why, is it really common where you live, or something? Are you from halfway around the world, oh my god I am so sorry if you are from halfway around the world. I will pay for a plane ticket back if I can't figure out how to put you back magically, I am so sorry!"
"...A plane ti- what year is this?"
"2004? ... Wait did I also do time travel? What the hell did I do?!"
"Last time I checked it was 2159 and no form of discovered magic looked like this thing, I have no idea what you did!"
"2159?! What?! I - how the hell did I even do that, it was supposed to be entirely based off of movement! There's - no form of discovered magic like this? But this is about the only magic we get! Do you just rely on - species specific things?!"
"Humans can summon daeva - with diagrams, just not diagrams like this - and get us to do things and there are some tiny parlor tricks that require no doodling on the floor, and that's it," says Cam. "So this is starting to sound like 'I have been pulled to an alternate multiverse' rather than 'time travel', although it is at least sort of also that, like, you're speaking English."
".... Holy shit I found a plane shift spell. Um. Okay, I can roll with this. Hi, I'm not actually human, I just happen to look like it right now. I'm a peryton, basically a magic deer with wings. You're a - daeva? Apparently?"
"Specifically I'm a demon. Daeva's a catchall for us and fairies and angels. In my multiverse, which doesn't have perytons."
"... By 'demon' how demony are we talking? Do I need to panic and run away screaming to my dad?"
Cam rolls his eyes. "You might if you'd gotten somebody other than me, but frankly anyone you'd have to run screaming from would not have let you talk this long, they'd have rendered you comatose to prevent dismissal as soon as they noticed that this isn't much of a diagram." He spreads his wingtips beyond the borders of the runes. "I'm not gonna hurt you."
"Eep," he squeaks. "... Okay, thank you for not rendering me comatose or - or possessing me or something, that would be bad, dad knows an angel but I doubt he could find one extremely quickly."
"...I can't possess you, and what would an angel do about it if I could?"
"Um. Hit you with a magic sword until you're banished back to Dis? I think that's how it goes?"
"...I'm not the relevant kind of demon. You can get rid of me by concentrating on doing it for about a minute, if you want, assuming the rules I'm used to are in play here as opposed to Crazy Peryton World Rules."
"Well if you're not the relevant kind of demon and not going to do terrible things, I don't have a problem with you sticking around as long as you like. Er. But my dad might, I should go tell him that I made a plane shift spell."
"Do you need me along for proof?"
"Nnnno he will believe me. Um. Do you want to go back to your home?"
"I'm not in a hurry. I'd like to make the next concordance with Limbo but that's not for years. And this assumes that you aren't going to wind up catapulting me into 1704 or 2378 or something by mistake, which I suppose I can't assume."
"... Yeah, I don't know that I won't do that by accident. That would be extremely bad. I am seriously very, very sorry about this! It was not what I was planning to do at all!"