To Harry, as he was taken off to the police station, it seemed the hardest sort of hard luck that his chase of Graves should be interrupted at such a critical time and just because he had been over-speeding. But he realized that he was helpless, and that he would only waste his breath if he tried to explain matters until he was brought before someone who was really in authority. Then, if he had any luck, he might be able to clear things up. But the men who arrested him were only doing their duty as they saw it, and they had no discretionary power at all.

When he reached the station he was disappointed to find that no one was on duty except a sleepy inspector, who was even less inclined to listen to reason than the constables.

"Everyone who breaks the law has a good excuse, my lad," he said. "If we listened to all of them we might as well close up this place. You can tell your story to the magistrate in the morning. You'll be well treated to-night, and you're better off with us than running around the country—a lad of your age! If I were your father, I should see to it that you were in bed and asleep before this."

There was no arguing with such a man, especially when he was sleepy. So Harry submitted, very quietly, to being put into a cell. He was not treated like a common prisoner; that much he was grateful for. His cell was really a room, with windows that were not even barred. And he saw that he could be very comfortable indeed.

"You'll be all right here," said one of the constables. "Don't worry, my lad. You'll be let off with a caution in the morning. Get to sleep now—it's late, and you'll be roused bright and early in the morning."

Harry smiled pleasantly, and thanked the man for his good advice. But he had no intention whatever of taking it. He did not even take off his clothes, though he did seize the welcome chance to use the washstand that was in the room. He had been through a good deal since his last chance to wash and clean up, and he was grimy and dirty. He discovered, too, that he was ravenously hungry. Until that moment he had been too active, too busy with brain and body, to notice his hunger.

However, there was nothing to be done for that now. He and Dick had not stopped for meals that day since breakfast, and they had eaten their emergency rations in the early afternoon. In the tool case on his impounded motorcycle Harry knew there were condensed food tablets—each the equivalent of certain things like eggs, and steaks and chops. And there were cakes of chocolate, too, the most nourishing of foods that are small in bulk. But the knowledge did him little good now. He didn't even know where the motorcycle had been stored for the night. It had been confiscated, of course; in the morning it would be returned to him.

But he didn't allow his thoughts to dwell long on the matter of food. It was vastly more important that he should get away. He had to get his news to Colonel Throckmorton. Perhaps Dick had done that. But he couldn't trust that chance. Aside from that, he wanted to know what had become of Dick. And, for the life of him, he didn't see how he was to get away.

"If they weren't awfully sure of me, they'd have locked me up a lot more carefully than this," he reflected. "And of course it would be hard. I could get out of here easily enough."

He had seen a drain pipe down which, he felt sure, he could climb.

"But suppose I did," he went on, talking to himself. "I've got an idea it would land me where I could be seen from the door—and I suppose that's open all night. And, then if I got away from here, every policeman in this town would know me. They'd pick me up if I tried to get out, even if I walked."

He looked out of the window. Not so far away he could see a faint glare in the sky. That was London. He was already in the suburban chain that ringed the great city. This place—he did not know its name, certainly—was quite a town in itself. And he was so close to London that there was no real open country. One town or borough ran right into the next. The houses would grow fewer, thinning out, but before the gap became real, the outskirts of the next borough would be reached.

Straight in front of him, looking over the housetops, he could see the gleam of water. It was a reservoir, he decided. Probably it constituted the water supply for a considerable section. And then, as he looked, he saw a flash—saw a great column of water rise in the air, and descend, like pictures of a cloudburst. A moment after the explosion, he heard a dull roar. And after the roar another sound. He saw the water fade out and disappear, and it was a moment before he realized what was happening. The reservoir had been blown up. And that meant more than the danger and the discomfort of an interrupted water supply. It meant an immediate catastrophe—the flooding of all the streets nearby.

In England, as he knew, such reservoirs were higher than the surrounding country, as a rule. They were contained within high walls, and, after a rainy summer, such as this had been, would be full to overflowing. He was hammering at his door in a moment, and a sleepy policeman, aroused by the sudden alarm, flung it open as he passed on his way to the floor below.

Harry rushed down, and mingled, unnoticed, with the policemen who had been off duty, but summoned now to deal with this disaster. The inspector who had received him paid no attention to him at all.

"Out with you, men!" he cried. "There'll be trouble over this—no telling but what people may be drowned. Double quick, now!"

They rushed out, under command of a sergeant. The inspector stayed behind, and now he looked at Harry.

"Hullo!" he said. "How did you get out?"

"I want to help!" said Harry, inspired. "I haven't done anything really wrong, have I? Oughtn't I be allowed to do whatever I can, now that something like this has happened?"

"Go along with you!" said the inspector. "All right! But you'd better come back—because we've got your motorcycle, and we'll keep that until you come back for it."

But it made little difference to Harry that he was, so to speak, out on bail. The great thing was that he was free. He rushed out, but he didn't make for the scene of the disaster to the reservoir, caused, as he had guessed, by some spy. All the town was pouring out now, and the streets were full of people making for the place where the explosion had occurred. It was quite easy for Harry to slip through them and make for London. He did not try to get his cycle. But before he had gone very far he overtook a motor lorry that had broken down. He pitched in and helped with the slight repairs it needed, and the driver invited him to ride along with him.

"Taking in provisions for the troops, I am," he said. "If you're going to Lunnon, you might as well ride along with me. Eh, Tommy?"

His question was addressed to a sleepy private, who was nodding on the seat beside the driver. He started now, and looked at Harry.

"All aboard!" he said, with a sleepy chuckle. "More the merrier, say I! Up all night—that's what I've been! Fine sort of war this is! Do I see any fightin'? I do not! I'm a bloomin' chaperone for cabbages and cauliflowers and turnips, bless their little hearts!"

Harry laughed. It was impossible not to do that. But he knew that if the soldier wanted fighting, fighting he would get before long. Harry could guess that regular troops—and this man was a regular—would not be kept in England as soon as territorials and volunteers in sufficient number; had joined the colors. But meanwhile guards were necessary at home.

He told them, in exchange for the ride, of the explosion and the flood that had probably followed it.

"Bli'me!" said the soldier, surprised. "Think of that, now! What will they be up to next—those Germans? That's what I'd like to know! Coming over here to England and doing things like that! I'd have the law on 'em—that's what I'd do!"

Harry laughed. So blind to the real side of war were men who, at any moment, might find themselves face to face with the enemy!