“You guard both these windows for a moment,” said Chester.  “I’ll lend Anderson a hand.”

He hurried back and arrived just in time to see the door swing inward.  Colonel Anderson, across the room from the door, stood in the shadow, waiting for the first of the enemy to show himself.

The door swung back violently and the men appeared in the opening in a body.  Chester and Colonel Anderson fired almost together.  Came hoarse cries from the attackers and a moment later the doorway was cleared.  Immediately Chester and the colonel hurled their weight against it, closing it again.

“Safe for a minute,” said Chester.

He hastened back to where he had left Helen and arrived just in time to see the girl fire her revolver at a figure that dashed toward the house.  The man did not falter.  Apparently the girl’s aim had been bad.  The man dashed to the very side of the house and took his stand directly under the window.

Chester poked his head out to see if he could pick the man off and as he did so his cap leaped from his head.  The lad heard something whiz by.  He withdrew his head quickly.

“Just missed me,” he said quietly.

Now three forms came dashing toward the house, running in a zig-zag course.

“See if you can get one of them,” cried Chester to the girl.

He took deliberate aim himself and fired.  One man dropped.

Helen also fired—­twice, but the other two men came on and joined the first arrival under the edge of the window.

“Great Scott!  This won’t do,” said Chester.  “We can’t have those fellows under there.  We’ll have to get them out some way.”

At that moment Colonel Anderson’s voice rang out: 

“Here they come again.”

Chester dashed back.  Again the door swung inward and two faces appeared, revolvers leveled before them.  They fired even as they came in sight and Colonel Anderson tumbled over with a sharp cry.

“They got me,” he said in a faint voice.

“And I got one of them!” shouted Chester as one of the Bulgarians hit the floor with a thud.

The other withdrew his head before Chester could fire again.

Chester raised his voice and called to Helen: 

“How are you making it?”

“All right,” the girl called back.  “Haven’t seen any one since you left.”

“Can you hold both windows?” demanded Chester.

“I think so.  Why?”

“Anderson has been hit.  I’ll have to stand guard here.  Pass the word to Ivan, will you?  Tell him of the men under the window.  He may be able to help you out.”

The girl did as Chester ordered.

Helen, standing close to the window, allowed her revolver to rest on the sill.  In the darkness, a hand appeared from below and grasped the weapon by the barrel and wrenched it from her grasp before she could pull the trigger.

Helen screamed.