Up till an hour ago, unless Lothar had been keeping an occult watch on Otto, he could not have been aware that they had traced him to Switzerland; but if the Chinese labourers had reported the Sergeant's visit that might have aroused Lothar's suspicions. With luck he would assume that only chance or a routine round had brought a local policeman to the engine-house, but his psychic perceptions being so acute it was possible that he would deduce a warning from it. If so, he was now overlooking their approach and, awful thought, if he had his rocket ready, that might precipitate his launching of it.

When they reached the hamlet Jodelweiss spoke into the car radio. He ordered one of the police cars behind them to stop, and its crew to search the hamlet in case any of the men from the engine-house or cave should have come down there since the Sergeant's visit, and be temporarily hiding in one of the barns. A few kilometres further on, as they came opposite the aircraft hangar, he detached another squad for a similar purpose.

All of them were now craning forward in their seats to catch the first glimpse of the cable railway up which forty-eight hours earlier the stolen war-head had been carried. At length they rounded a last bend and came in full view of it. Half a mile ahead lay the engine-house. Beyond it, in the distance, far up the valley and on its opposite side from the railway, a little group of figures were moving. They were making their way up a broad gully towards a dip in the ridge and were visible only because they had already passed the snow line.

The Brigadier spoke into the walkie-talkie he was carrying, ordering two jeeps filled with ski-troops to go after them and bring them in; but the sight of the group, which was so obviously making off, was enough to tell Verney that his fears had been well founded. The Sergeant's visit two hours earlier must have alerted Lothar to the fact that Switzerland was being combed for him. Since then, no doubt, he would have used his psychic powers to detect and observe the advancing column of police and troops.

Two minutes later the leading cars pulled up outside the engine-house. Their occupants tumbled out. Armed police and troops dashed inside. A Lieutenant emerged again almost at once and shouted, 'The place is empty, but the cage is down here.'

C.B. was staring after the tiny figures that stood out against the snow, and wondering now if Lothar was one of them. Barney tugged at his sleeve and cried, 'Come on, the cabin's here! Come on, or there won't be room for us in it.'

'Half-a-mo', partner,' C.B. replied. 'The bird we are after may have fled the nest. Maybe he's one of those little moving dots up there.'