"This is the gate we want," he cried.

But a third spit of flame came from the darkness overhead, and Paul heard the overseer swearing softly under his breath. Whoever their unknown assailant might be, he was no mean marksman.

Paul and Alexis ran to Andrieff's aid.

"What's up?" asked Paul.

"Nothing," answered Andrieff, and he got the gate opened. The three men dashed up the path and reached a small door; but it was made of stout oak, and securely fastened within.

They thrust their shoulders against it without avail, and then stood looking at one another, panting, and for the moment baffled.

It was then that Paul's quick ear caught a woman's voice. He whipped round and looked across the sheet of water. His eyes were now well accustomed to the gloom, and he saw the form of a woman leaning far out of a window and gesticulating wildly.

He held up his hand to the others for silence, and then once more came a voice which he instantly recognized. It was the voice of the red-haired woman.

"Be quick! Be quick!" she cried. "If you don't wish to be too late, you must swim the moat—the door is barred."

Paul cast a quick glance behind him, and his eyes fell on the gate.