And then, in a flash, the possible solution of it all came to him.
Had Culver Rann discovered the secret mission on which he and the old mountaineer were going into the North?
Had he learned of the gold--where it was to be found?
And was their assassination the first step in a plot to secure possession of the treasure?
The blood in Aldous' veins ran faster.

He gripped his pistol harder.

More closely he looked into the moonlit gloom of the trail ahead of him.

He believed that he had guessed the meaning of MacDonald's warning.

It was the gold! More than once thought of the yellow treasure far up in the North had thrilled him, but never as it thrilled him now.