Chapter 31 I carefully fed the rolled up fire blanket through the hole to Harry. He draped it over his head and crouched down so it gave some protection from the sword’s heat. ‘I’ve felt the boundary in a few places,’ he said. ‘It’s always right up against the cliff face, though, so there’s nowhere to go. I’ve spent all day exploring caves and tunnels with no luck. They all either stop or twist around and head back out again. I get the impression the boundary runs along the full length of the cliff. At the southern edge I felt nothing. Like a wall that just finishes where the cliff starts to descend to the river. I haven’t been to the northern end but I would guess that the same thing happens. The Event Horizon has been neatly set up to coincide with the one place that’s physically inacc

