Very, very quietly the boat edged into the loch from the sea. Ahead, to the east, a line of grey announced that daybreak was near. The night vision camera revealed the house near the shore and two tents at its side. A pinprick of light was pointed at the incoming craft, on and off, making out a message in Morse code. What the night vision camera did not spot was the evidence that the message was futile, as the object of the communication had moved out of sight. The other tent was empty.