Little time was lost in securing the two men who had been so effectively rendered helpless by Koku's ready, if rough, measures. One of them was showing signs of returning consciousness now, and Tom, not willing to inflict needless pain, even on an enemy, told one of his men, summoned by the alarm, to bring water. Soon the two men opened their eyes, and looked about them in dazed fashion.
"Did—did anything hit me?" asked one meekly.
"It must have been a thunderbolt," spoke the other dreamily. "But it didn't look like a storm."
"Oh, dere was a storm, all right," chuckled Eradicate, who, having left his mule, Boomerang outside, came into the shed. "It was a giant storm all right."
The men put their hands to their heads, and seemed to comprehend. They looked at the rope that bound their feet. Their forearms had been loosened to allow them to take a drink of water.
"What does this mean—Ransom—Kurdy?" asked Tom sternly, when the men seemed able to talk. "Did you attack Koku?"
"It looks as though he had the best of us, whether we did or not," said the man Tom knew as Kurdy. "Whew, how my head aches!"
"Me sorry," said Koku simply.
"Not half as sorry as we are," returned Ransom ruefully.
"What does it mean?" asked Tom sternly. "There were four of you. Feldman and one other got away."
"Oh, trust Feldman for getting away," sneered Kurdy. "He always leaves his friends in the lurch."
"Was this a conspiracy?" demanded Tom.
The two captives looked at one another, sitting bound on the floor of the shop, their backs against some boxes.
"I guess it's all up, and we might as well make a clean breast of it," admitted Kurdy.
"Perhaps it would be better," said Tom quietly. "Eradicate," he went on, to the colored man, "go to the house and tell Mrs. Baggert that everything is all right and no one hurt."
"No one hurt, Massa Tom? What about dem dere fellers?" and the colored man pointed to the captives.
"Well, they're not hurt much," and Tom permitted himself a little smile. "I don't want my father to worry. Tell him everything is all right."
"All right, Massa Tom. I'se gwine right off. I'se got t' look after mah mule, Boomerang, too. I'se gwine," and he shuffled away.
"Who else besides Feldman got away?" asked Tom, looking alternately at the prisoners.
They hesitated a moment about answering.
"We might as well give up, I tell you," spoke Kurdy to Ransom.
"All right, go ahead, we'll have to take our medicine. I might have known it would turn out this way—going in for this sort of thing. It's the first bit of crooked business I ever tried," the man said earnestly, "and it will be the last—believe me!"
"Who was the fourth man?" Tom repeated.
"Harrison," answered Kurdy, naming one of the most efficient of the new machinists Tom had hired during the rush.
"Harrison, who has been working on the motor?" cried the young inventor.
"Yes," said Ransom.
"I'm sorry to learn that," Tom went on in a low voice. "He was an expert in his line. But what was your object, anyhow, in attacking Koku?"
"We didn't intend to attack him," explained Ransom, "but he came in when we were at work, and as he went for us we tried to stand him off. Then your colored man heard the racket, and—well, I guess you know the rest."
"But I don't understand why you came into this shed at night," went on Tom. "No one is allowed in here. You had no right, and Koku knew that. What did you want?"
"Look here!" exclaimed Kurdy, "I said we'd make a clean breast of it, and we will. We're only a couple of tools, and we were foolish ever to go in with those fellows; or rather, in with that Frenchman, who promised us big money if we succeeded."
"Succeeded in what?" demanded the young inventor.
"In damaging your new aerial warship, or in getting certain parts of it so he could take them away with him."
Tom gave a surprised whistle.
"A frenchman!" he exclaimed. "Is he one of the—?"
"Yes, he's one of the foreign spies," interrupted Ransom. "You'd find it out, anyhow, if we didn't tell you. They are after you, Tom Swift, and after your machines. They had vowed to get them by fair means or foul, for some of the European governments are desperate."
"But we were only tools in their hands. So were Feldman and Harrison, but they knew more about the details. We were only helping them."
"Then we must try to capture them," decided Tom. "Ned, see if the chase had any results. I'll look after these chaps—Koku and I."
"Oh, we give in," admitted Kurdy. "We know when we've had enough," and he rubbed his head gently where the giant had banged it against that of his fellow-conspirator.
"Do you mean that you four came into this shop, at midnight, to damage the Mars?" asked Tom.
"That's about it, Mr. Swift," replied Kurdy rather shamefacedly. "We were to damage it beyond repair, set fire to the whole place, if need be, and, at the same time, take away certain vital parts.
"Harrison, Feldman, Ransom and I came in, thinking the coast was clear. But Koku must have seen us enter, or he suspected we were here, for he came in after us, and the fight began. We couldn't stop him, and he did for us. I'm rather glad of it, too, for I never liked the work. It was only that they tempted me with a promise of big money."
"Who tempted you?" demanded Tom.
"That Frenchman—La Foy, he calls himself, and some other foreigners in your shops."
"Are there foreigners here?" cried Tom.
"Bless my chest protector!" cried Mr. Damon, who had come in and had been a silent listener to this. "Can it be possible?"
"That's the case," went on Kurdy. "A lot of the new men you took on are foreign spies from different European nations. They are trying to learn all they can about your plans, Mr. Swift!"
"Are they friendly among themselves?" asked Tom.
"No; each one is trying to get ahead of the other. So far the Frenchman seems to have had the best of it. But to-night his plan failed."
"Tell me more about it," urged Tom.
"That's about all we know," spoke Ransom. "We were only hired to do the rough work. Those higher up didn't appear. Feldman was only a step above us."
"Then my suspicions of him were justified," thought Tom. "He evidently met La Foy in the woods to make plans. But Koku and Eradicate spoiled them."
The two captives seemed willing enough to make a confession, but they did not know much. As they said, they were merely tools, acting for others. And events had happened just as they had said.
The four conspirators had managed, by means of a false key, and by disconnecting the burglar alarm, to enter the airship shed. They were about to proceed with their work of destruction when Koku came on the scene.
The giant's appearance was due to accident. He acted as a sort of night watchman, making a tour of the buildings, but he entered the shed where the Mars was because, that day, he had left his knife in there, and wanted to get it. Only for that he would not have gone in. When he entered he surprised the four men.
Of course he attacked them at once, and they sprang at him. Then ensued a terrific fight. Eradicate, arising to doctor his mule, as he had said, heard the noise, and saw what was going on. He gave the alarm.
"Well, Ned, any luck?" asked Tom, as his chum came in.
"No, they got away, Tom. I had a lot of your men out helping me search the grounds, but it wasn't of much use."
"Particularly if you depended on some of my men," said Tom bitterly.
"What do you mean?"
"I mean that the place is filled with spies, Ned! But we will sift them out in the morning. This has been a lucky night for me. It was touch and go. Now, then, Koku, take these fellows and lock them up somewhere until morning. Ned, you and I will remain on guard here the rest of the night."
"I'm with you, Tom."
"Will you be a bit easy on us, considering what we told you?" asked Kurdy.
"I'll do the best I can," said Tom, gently, making no promises.
The two captives were put in secure quarters, and the rest of the night passed quietly. During the fight in the airship shed some machinery and tools had been broken, but no great amount of damage was done. Tom and Ned passed the remaining hours of darkness there.
A further search was made in the morning for the two conspirators who had escaped, but no trace of them was found. Tom then realized why Feldman was so anxious to be placed in the aeroplane department—it was in order that he might have easier access to the Mars.
A technical charge was made against the two prisoners, sufficient to hold them for some time. Then Tom devoted a day to weeding out the suspected foreigners in his place. All the new men were discharged, though some protested against this action.
"Probably I am hitting some of the innocent in punishing those who, if they had the chance, would become guilty," Tom said to his chum, "but it cannot be helped—I can't afford to take any chances."
The Mars was being put in shape for her first flight. The guns, fitted with the recoil shock absorbers, were mounted, and Lieutenant Marbury had returned to go aloft in the big aerial warship. He congratulated Tom on discovering at least one plot in time.
"But there may be more," he warned the young inventor. "You are not done with them yet."
The Mars was floated out of her hangar, and made ready for an ascent. Tom, Ned, Lieutenant Marbury, Mr. Damon, and several workmen were to be the first passengers. Tom was busy going over the various parts to see that nothing had been forgotten.
"Well, I guess we're ready," he finally announced. "All aboard!"
"Bless my insurance policy!" exclaimed Mr. Damon. "Now that the time comes I almost wish I wasn't going."
"Nonsense!" exclaimed Tom. "You're not going to back out at the last minute. All aboard! Cast off the ropes!" he cried to the assistants.
A moment later the Mars, the biggest airship Tom Swift had ever constructed, arose from the earth like some great bird, and soared aloft.