'He'd never have abandoned his rocket at this stage,' Barney argued quickly. 'I swear he'd die rather. And if . . . if Mary's not dead, she will be with him.'

'If the rocket was all fixed to go, he might have. He could have left it with a time fuse attached to launch it. Anyhow, the rocket is first priority. These cable-railway cages usually hold only four, and the Brigadier told me that he had been ordered to bring explosive experts with him. I'm sorry, Barney, but we must let them go ahead so that they may have the best possible chance to get at that war-head in time to dismantle it. But Lothar is our pigeon, and getting him our best hope of saving Mary. If he is one of those dots up there we must go after him.'

With a murmured apology Barney almost snatched a pair of field-glasses from an officer who was standing nearby. Swiftly he focused them on the distant figures and, after a moment, said, 'There are seven of them. That is two in addition to the five Chinks that the Sergeant found down here in the engine-house. None of them looks like a woman; but in those clothes one can't tell. Anyhow, Colonel Washington's not one of them. I'm sure of that because of his height.'

At that moment there came the sudden crack and roar of an explosion. Its blast flung them both forward on their knees. As they picked themselves up they looked round to find that the engine-house was now a smoking ruin. Shouts and screams were coming from it. Troops and police were running to the assistance of their wounded comrades. For a few minutes everything was confusion.

As the smoke above the wrecked building cleared Barney suddenly shouted, 'Look! Look! There he is. The explosion has brought the murdering swine out to see the results of his handiwork.'

Following Barney's pointing ringer, C.B. saw that a figure had emerged from the cave and was now standing on the edge of the broad ledge, looking down through a pair of glasses at the scene of havoc. He, too, had no doubt that it was Lothar.

Richter staggered up to them, his face blackened, his eyebrows singed and his uniform torn.

'What happened?' Verney asked him.

The American was still panting. 'That devil had booby-trapped both the cage and the engine. I chanced to be looking towards the winding gear as a corporal pushed over the lever. Both bombs went off simultaneously. The Brigadier and Jodelweiss were both in the cage. With them and in the freight compartment they had several sappers; bomb experts. All of them are to hell and gone. So are six or eight fellers who were standing round the engine. I was lucky. I couldn't get a place in the cage but I was standing alongside it by the opening. So I was blown clear.'