Whatever the noise was, it made them both suddenly duck their heads, utterly bewildered. Then they heard the drone of a helicopter, coming in low from the west. It had to be one of the IWS-licensed super-stealths; the thing was almost over the far wall before they heard it. Serrin began his spellcasting as Geraint desperately tried to revise his plan of action, waiting for the chopper to land, certain that this must be their man. The sudden flare took him completely by surprise, ruining his aim.