"I could renew it before it wore off if the guard in question has already cast it today, or if we stopped for tea and crumpets. Just making sure."
"We're just about there," he informs them. "So we should probably stop and finish charging all our preparation spells, first."
Iobel starts charging her invisibility. "I don't have a premature ending contingency - I wrote one, but couldn't cram it in with everything else - so when I start being invisible I'll stay that way for an hour," she warns.
"If I hand you a thing to identify yourself with, like a cloth or something, does it go invisible, too?"
"That part I'm very proud of - I can incorporate new stuff into the invisibility if I want to at the time it's attached or given to me. So if you want me to carry a cloth after I've done the requisite wall-walking I can not-invisible it."
"Aha. Okay, then after we're done we give you a cloth and use that to not run into you. No downsides, we're good."
"And it means the 'dump a bag of flour on her' trick doesn't work. Except by making me sneeze, anyway."
"That's fine. We can wait, we're already waiting for Ari's. Six minutes, right?"
Iobel charges and waits. "What's the layout of the house like, and what's his eyeshine color so I can recognize him through the perception spell?"
"I've never been on the inside of his house, so I've got no idea, but his eyeshine color is a lavender."
"Three, I think. Maybe a fourth as an attic, but I doubt that would come up."
"Ooo. Okay, in that case - when your invisibility spell goes, you go look around the house while charging the wall walking spell."
It makes him rather sad to realize that and he inspects his shoes.
"I might not even need to go into the house to knock him out, if he's on the first floor and there's a window open."