ripple or plash, which might betray their movements to suspicious ears
upon the battlements (if indeed any sort of watch were kept, which
appeared doubtful). They swam with that perfect silence possible only to
those who are thoroughly at home in the water, till they had crossed the
dark moat and had reached the perpendicular wall of the Tower, which
rose sheer upon the farther side -- so sheer that not even the foot of
mountain goat could have scaled its rough-hewn side.

But Gaston knew what he had to search for, and with outstretched hand he
swam silently along the solid masonry, feeling for that aperture just
above watermark which he had seen before the daylight faded. It took him
some little time to find it, but at last it was discovered, and with a
muttered word of command to the men who silently followed in his wake,
he drew himself slowly out of the water, to find himself in a very
narrow rounded aperture like a miniature tunnel, which trended slightly
upwards, and would only admit the passage of one human being at a time,
and then only upon hands and knees.

It was pitchy dark in this tunnel, and there was no space in which to
attempt to kindle a light. Once the thought came into Gaston's head that
if he were falling into a treacherous pitfall laid for him with diabolic
ingenuity by his foes, nothing could well be better than to entrap him
into such a place as this, where it would be almost impossible to go
forward or back, and quite out of his power to strike a single blow for
liberty or life.

But he shook off the chill sense of fear as unworthy and unknightly. His
Constanza was true; of that he was assured. The only possible doubt was
whether she herself were being used as an unconscious tool in the hands
of subtle and perfectly unscrupulous men.

But even so Gaston had no choice but to advance. He had come to rescue
his brother or to die with him. If the latter, he would try at least to
sell his life dearly. But he was fully persuaded that his efforts would
be crowned with success.

He had time to think many such things as he slowly crept along the low
passage in the black darkness. It seemed long before his hand came in
contact with the door he had been told he should presently reach, and
this door, as Constanza had said, yielded to his touch, and he felt
rather than saw that he had emerged into a wider space beyond.

This place, whatever it was, was not wholly dark, though so very dim
that it was i