He feels an open summons and lets it grab him -
The king is hugging his fairy more tightly than is probably necessary considering that they're levitating.
Cam flies away in his spaceship, the fairy and her king fly away with her bringing the air around them along too speedily enough to be comfortable, and Cam lands at Camelot in a fog.
When he sees Cam, "Welcome back. The wars are over, such as they were."
Next on the unending list we've got the edited constitution to distribute, we can get changers now to speed up the railroad building, and of course your Mars project. Any preferences for the order?"
"Not picky about the ordering. Mars can wait, I don't have anyone to put on it yet no matter how I pretty it up. But you are in for one heck of a safety lecture before I teach you to summon anything other than me personally and specifically."
"Right, you mentioned the lack of incentives to not destroy the world. All right, how do we screen for sane people?"
"That's not really the level on which I mean to safety-lecture you. Like, if you want to hire somebody repeatedly it should be someone sane and friendly and smart - but if you're sifting through random angels, pardon, changers, you need bindings."
"Fair enough. Given enough random changers, the continued existence of earth isn't something to take chances with. How do the bindings work, then?"
"I can give you books. The basic idea is - work in your native language, don't get cute, actually check for loopholes, and elegance and convenience means squat if it leaves a changer the leeway to turn your brains into mashed potatoes."
"Anyone with hundreds of years of experience taking summons is probably better at loopholes than I am at avoiding them. I might just stick with unedited, known safe summons from those books until I'm sure the daeva in question isn't a malevolent being of pure evil."
"That is a solid approach. I can also draw most of a circle for you without the possibility of incorrect transcription as long as you make the last mark."
"That sounds even safer, but limits summoning to whenever you're here. Would it work if you make a stack of papers with circles, or make a floor with most of a circle carved in it?"
"Papers work, carving won't more than once unless you pour water into it or something each time - and I can't make the paper secure against attempts by other people to use them. Nor for that matter a carving."
Well, this castle is riddled with secret compartments and passages; nobody'll notice one more hidden bookshelf."
"I suppose you could put a carving under a rug, but it will have to stay unrugged the entire time you have a changer in it for negotiations or pending dismissal."
Better to stick with the books and a few pre-made papers. Those I can hide indefinitely."
"Sure. I can do them mostly in invisible ink, it occurs to me - as long as you have the same thing in your pen you can finish them if I indicate where to draw in some visible material."
Let's go for it.
Anything else I need to know before summoning one? What kind of payment do changers usually ask for?"
"I can pay changers pretty easily. When I'm not around, of things you can procure here, they may also be willing to take pets - I assume there are dogs and cats around - and potted plants and reading material and interesting art objects."
He leads the way down to the nearest cellar. "This isn't the most comfortable part of the castle, but we don't need to worry about being seen or heard down here."
"No reason not to, as long as nothing looks too out of place. And there's leeway on that front; nobody wonders why someone hung a tapestry in a cellar and arrives at the conclusion that it was magic."
"Maybe I'd better be here for a little longer before I start trying to make decorating decisions based on what will or will not look out of place, though."
Anyway, shall we try for a changer?"