Two men alighted, and went in the same direction as the one who had gone ahead.
Francis made a detour, so as to avoid being noticed by the gondoliers, and then again followed.

After keeping more than a quarter of a mile near the water, the two figures ahead struck inshore.

Francis followed them, and in a few minutes they stopped at a black mass, rising above the sand.

He heard them knock, and then a low murmur, as if they were answering some question from within.

Then they entered, and a door closed.
He moved up to the building.