Presently, he heard a grating sound against the window.

It was very dark, and he knelt down so that he would be able to make out any figure that showed above the windowsill.

He thought first of rousing his master, but as he had another pistol in his belt, and his sword leaned against the wall, ready to his hand, he thought it better to let matters take their course.
He had heard no further sound, but presently a round object appeared in sight.

Stretching out his arm, he fired without a moment's hesitation.

There was a sound of a heavy fall below, followed by some muttered exclamations.