"Hi," she says when they walk in.
"I have your phone." She hands Promise a mortal artifact of the appropriate type.
Royal is happy to explain the basic functions of this mortal artifact.
"Is there a particular time at which I should call Castle? I imagine it would be alarming to have this thing start making noises unexpectedly."
"It's customary to avoid calling people when they're likely to be sleeping or have recently woken up, unless there's an emergency. You can assume Castle is awake and willing to receive calls anytime from late morning until a few hours after sundown."
"Now, was there anything else you wanted to look up while you're here?"
"What are the odds you've already found and taken possession of the Gem of Amara?"
"I haven't. Yet," she says. "But you're right that it would be fairly pointless for you to try to catch up to what I've been able to find out from these books. If I'm impressed with how you handle your sun ward I will tell you everything I know about where to find it, and if I'm not, I'll have a significant head start."
"I'll leave it in your hands, then," he shrugs. "Promise, shall I fetch your books so you can pick up where you left off?"
Rather than do research of his own, Tea idly engages Royal in a game of chess without an actual chessboard. They just narrate the moves to each other out loud.
What a peculiar skill to have. Promise can't follow the notation at all. She reads. Her access to her tree let her get at some notebooks, including one that started the day empty and between the two libraries is approaching half-full.
Meanwhile, Tea and Royal intersperse their impenetrable chess match with only-slightly-less-impenetrable conversation. At least they seem to be getting along.
That's nice for them. Promise will just take frustrated outside-perspective notes. Maybe she will invent a version of this magic system that works for her the way chess magic works for Castle.
"I'm going to want to call Castle tomorrow about it. I'm sure I could just read every book on magic in this and a dozen other libraries and wind up relatively expert compared to a human, but only by spending a human lifetime on it. I'd sooner take a shortcut, at least for immediate practical purposes. I have no strong understanding of chess but perhaps I can invent something else that suits me and fills in the gaps sorcery has."