"Don't you know of the boathouse near Milikoff's place?"
Hallo's tone was suddenly menacing. Dick could imagine that he was leaning forward, pushing his heavy jaw into the face of the other man. He remembered that trick of the Hungarian's.
"Boathouse—near Milikoff's? No!" stammered the other. "I never heard of it before!"
"H'mph!" Hallo's voice expressed doubt, distrust. "Perhaps not! Well, I came upon it by chance to-night, and it saved my life. They seized me to-night when I was in conference with them—the treacherous hounds! But they are Servians! I might have expected it! I escaped, and they chased me! They chased me right into the Danube! I swam, while they peppered the water. They had those new silencers, so that it was safe to shoot. And by the merest chance, when I was nearly exhausted, I suddenly saw a door in front of me, as I was trying to swim ashore in an inlet, in the hope of escaping after I had landed. I dived, and came up in a boathouse. The door could be raised, you see, to admit a boat. There was a closet, and I hid."
"That is news to me! I never heard that there was such a place!"
"I drew the closet door to when I heard a man come in. Soon afterward a motor boat entered, and two men landed from her. I could hear their voices dully—that closet door was thick, and it was so hot and close inside that I was almost suffocated. I do not know who they were except that I think Vanya, the soldier, was the man who opened for them. Later, when they had gone, I got out and came here."
"It is good that you came. Master, it is to-night that they plan to strike a great blow. They have dug a tunnel beneath the arsenal. I am almost sure that it is to-night they have chosen to explode a great mine that will destroy the arsenal completely, with all the stores and guns it contains!"
Hallo swore savagely.
"You have done well!" he said. "Eh, there is time yet, you think, to stop them? How is it that you do not know more concerning their plans?"
"They do not trust me wholly. I know only what I can learn by spying and ferreting about. They tell me almost nothing. But I am sure that I am right. Look—I will draw you a plan that will show you where the tunnel is. I think that if you hasten you can catch most of them like rats in a trap. Milikoff is not there. He is the most dangerous of all, save one."