But there was an undercurrent of deeper sound--water surely, water churning among rocks.

It was a stream--the Garple of course--and then he remembered where he was and what had happened.
I do not wish to portray Dickson as a hero, for nothing would annoy him more; but I am bound to say that his first clear thought was not of his own danger.

It was intense exasperation at the miscarriage of his plans.

Long ago he should have been with Dougal arranging operations, giving him news of Sir Archie, finding out how Heritage was faring, deciding how to use the coming reinforcements.

Instead he was trussed up in a wood, a prisoner of the enemy, and utterly useless to his side.
He tugged at his bonds, and nearly throttled himself.