"Oh, thank you--ever so much," she murmured. "Of course it wasn't our fault, but I feel sorry for the poor fellow. Tell the doctor to send me the bill."

She and Del Mar shook hands. I thought he held her hand perhaps a little longer and a little tighter than usual. At any rate Elaine seemed to think so.

"Why, what a curious ring, Mr. Del Mar," she said, finally releasing her own hand from his grasp.

Then she looked quickly at the woman, half joking, as if the ring had something to do with the strange woman. She looked back at the ring.

Del Mar smiled, shook his head and laughed easily.

Then Elaine picked up her bag and we went out. A moment later we climbed back into the car and were off again.

Having left us at the door, Del Mar hurried back to the library. He went straight to the desk and picked up the book, eager now to make sure of the safety of the plan.

It was gone!

"Did you, Smith--" he began hastily, then checked himself, knowing that the clerk had not taken the plan.

Del Mar walked over to the couch and stood a moment looking at the chauffeur. "I wonder who he is," he said to himself. "I don't recall ever seeing him at the station or in the village."

He leaned over closer. "The deuce!" he exclaimed, "that's a fake beard the fellow has on."

Del Mar made a lunge for it. As he did so, the chauffeur leaped to his feet and drew a gun. "Hands up!" he shouted. "And the first man that moves is a dead one!"

Before the secret agent knew it, both he and Smith were covered. The chauffeur took a step toward Smith and unceremoniously jerked off the widow's weeds, as well as the wig.

At that very moment one of Del Mar's men came up to the secret panel that opened from the underground pa.s.sageway into his library. He was about to open it when he heard a sound on the other side that startled him. He listened a moment, then slid it just a short distance and looked in.

There he saw a chauffeur holding up Del Mar and Smith. Having pulled the disguise from Smith, he went next around Del Mar and took his gun from his pocket, then pa.s.sed his hands over the folds of Smith's dress, but found no weapon. He stepped back away from them.

At that point the man quietly slid the panel all the way open and silently stepped into the room, behind the chauffeur. Cautiously he began sneaking up on him.

As he did so, Del Mar and Smith watched, fascinated. Somehow their faces must have betrayed that something was wrong. For, as the newcomer leaped at him, the chauffeur turned suddenly and fired. The shot wounded the man.

It was a signal for a free-for-all fight. Del Mar and Smith leaped at the intruder. Over and over they rolled, breaking furniture, overturning and smashing bric-a-brac.

Del Mar's revolver was knocked out of the chauffeur's hand. With a blow of a chair, the chauffeur laid out Smith, entangled in his unfamiliar garments, shook himself loose from the two others, and made a rush at the door.

Del Mar paused only long enough to pick up the revolver from the floor.

Instantly he fired at the retreating form. But the chauffeur had pa.s.sed out and banged shut the door. Down the walk he sped and out to the gate, into his car, the engine of which he had left running.

Hard after him came Del Mar and the rest, joined now by Henry, the valet. One shot was left in the chauffeur's revolver and he blazed away as he leaped into the car.

"He's got me," groaned Smith as he stumbled and fell forward.

On kept Del Mar and the others. They caught up with the car just as it was starting. But the chauffeur knocked the gun from Del Mar's hand before he could get a good aim and fire, at the same time bowling over the man who had come through the panel.

Off the car went, now rapidly gaining speed. Del Mar had just time to swing on the rear of it.

Around the rapidly-driven car, he climbed, hanging on for dear life, over the mud-guard and toward the running-board. On sped the car, swaying crazily back and forth, Del Mar crouched on the running-board and working his way slowly and perilously to the front seat.

The chauffeur felt the weight of some one on that side. Just as he turned to see what it was, Del Mar leaped at him. Still holding the wheel, the chauffeur fought him off with his free hand, Del Mar holding on to some spare tires with one hand, also. Handicapped by having the steering-wheel to manage, nevertheless the chauffeur seemed quite well able to give a good account of himself.

Somehow, Elaine and I must have been hoodooed that day.

We had not been gone five minutes from Del Mar's after the accident to the chauffeur, when we heard a mysterious knock in the engine.

"More engine trouble," I sighed. "Pull up along the road and I'll see if I can fix it."

We stopped and both got out. There was no fake about this trouble or about the dirt and grease I acquired on my hands and face, tinkering with that motor. For, regardless of my immaculate flannels, I had to set to work. A huge spot of grease spattered on me. Elaine laughed outright.

"Here, let me powder your nose, Walter," she cried undismayed at our trouble, gayly opening her bag. "Well--of all things--what's this, and where did it come from?"

I turned from the engine and looked. She was holding some kind of plan or doc.u.ment in her hand. In blank surprise she examined it. It looked like a fort or a series of forts. But I was sure at a glance that it was not Fort Dale.

"What do you think it is, Walter?" she asked, handing it to me.

I took it and examined it carefully. Incredible as it seemed, I figured out quickly that it must be nothing short of a plan of the new defenses at Sandy Hook.

"I don't know what it all means," I said. "But I do know that we won't get any dinner till I get this engine running again."

I fell to work again, eager to get away with our dangerous prize, Elaine now and then advising me. Finally I turned the engine over. For a wonder it ran smoothly. "Well, that's all right, at last," I sighed, wiping the grease off my hands on a piece of waste.

"What's the matter now?" exclaimed Elaine, turning quickly and looking up the road along which we had just come.

There, lurching along at full speed was a car. Two men were actually fighting on the front of it regardless of speed and safety. As it neared us, I saw it was the taxicab that had been standing before Del Mar's. I looked closer at it. To my utter amazement, who should be driving it but the very chauffeur whom we had left at Del Mar's only a few minutes before, apparently unconscious. He could not have been hurt very badly, for he was not only able to drive but was fighting off a man clinging on the running-board.

On rushed the car, directly at us. Just as it pa.s.sed us, the chauffeur seemed to summon all his strength. He struck a powerful blow at the man, recoiled and straightened out his car just in time. The man fell, literally at our feet.

It was Del Mar himself!

On sped the taxicab. Bruised though he must have been by the fall, Del Mar nevertheless raised himself by the elbow and fired every chamber of his revolver as fast as he could pump the bullets.

I must say that I admired the man's pluck. Elaine and I hurried over to him. I still had in my hand the queer paper which she had found so strangely in her hand-bag.

"Why, what's all this about?" I asked eagerly.

Before I could raise him up, Del Mar had regained his feet.

"Just a plain crook, who attacked me," he muttered, brushing off his clothes to cover up the quick recognition of what it was that I was holding in my hand, for he had seen the plan immediately.

"Can't we drive you back?" asked Elaine, quite forgetting our fears of Del Mar in the ugly predicament in which he just had been. "We've had trouble but I guess we can get you back."

"Thank you," he said, forcing a smile. "I think anything would be an improvement on my ride here and I'm sure you can do more than you claim."

He climbed up and sat on the floor of the roadster, his feet outside, and we drove off. At last we pulled up at Dodge Hall again.