I was sure that was it, we were dead, but somehow the rest of the ceiling held and we were still alive when, gasping and choking on the dust she'd created, Ruth Wilkins staggered through the secret door and into the room.

"We have to go!" She shouted like she'd been partially deafened and perhaps she had. She certainly looked like she'd come too close to an explosion, the side of her face peppered with little cuts, one hand cradled against her as if damaged by flying ...