Arethusa by F. Marion Crawford

Zeno found the two occupants of the room terrorstruck, and standing on one side of the window, from which they had not dared to look out after the cry of alarm had been given from below. Indeed they were in a dangerous pass, unless all three of the men who had attempted to stop Zeno were dead, or if the first cry had roused the sleeping captain and guards of the tower from their drugged sleep.

But Zeno's own situation was quite as bad. It was out of the question to shout to Gorlias, on the mere chance of his being still alive and on the pier. No communication was possible, and the rope was cut below. It was true that the whole of the fishing-line still lay coiled on the floor of the room, but even if it were long enough to double it would hardly bear the man's weight; and Carlo guessed that he had cut off nearly three-quarters of the knotted rope below him.