Arthur was about to kneel down and help clean up the mess, but then he sees what Stiles is doing and he sets his jaw with a sigh. He doesn't move quickly, but once he does move it's with purpose - he takes a few steps toward the desk, picks up Stiles' books with one hand and then grabs the back of Stiles' shirt with the other.

"Time to go, kid."

He pulls him up off the desk and then pushes him toward the door, marching him out of the bookstore and onto the sidewalk outside, stopping a few feet away from the storefront.