After only an instant’s hesitation, Rafael ran headlong across the room, throwing his shoulder against the wall. I expected to hear a splintering crash, but instead he just vanished through the bricks as though they weren’t even there. I heard him land with a thud somewhere beyond the wall, then roar in pain. He’d probably landed on his injured wrist. And that’s when I realized what I was looking at: an illusion. The wall—or at least, that section of it—didn’t really exist.