“Ugh!” shuddered Rod.  “This cabin hasn’t had any fresh air in it for a century, I’ll bet.  Let’s get out!”

Mukoki, in passing, picked up a skull from the heap of bones near the chair.

“Dog!” he grunted.  “Door lock’—­window shut—­men fight—­both kill.  Dog starve!”

As the three retraced their steps to the spot where Wolf was guarding the toboggan, Rod’s imaginative mind quickly painted a picture of the terrible tragedy that had occurred long ago in the old cabin.  To Mukoki and Wabigoon the discovery of the skeletons was simply an incident in a long life of wilderness adventure—­something of passing interest, but of small importance.  To Rod it was the most tragic event that had ever come into his city-bound existence, with the exception of the thrilling conflict at Wabinosh House.  He reconstructed that deadly hour in the cabin; saw the men in fierce altercation, saw them struggling, and almost heard the fatal blows as they were struck—­the blows that slew one with the suddenness of a lightning bolt and sent the other, triumphant but dying, to breathe his last moments with his back propped against the wall.  And the dog!  What part had he taken?  And after that—­long days of maddening loneliness, days of starvation and of thirst, until he, too, doubled himself up on the floor and died.  It was a terrible, a thrilling picture that burned in Roderick’s brain.  But why had they quarreled?  What cause had there been for that sanguinary night duel?  Instinctively Rod accepted it as having occurred at night, for the door had been locked, the window barred.  Just then he would have given a good deal to have had the mystery solved.

At the top of the hill Rod awoke to present realities.  Wabi, who had harnessed himself to the toboggan, was in high spirits.

“That cabin is a dandy!” he exclaimed as Rod joined him.  “It would have taken us at least two weeks to build as good a one.  Isn’t it luck?”

“We’re going to live in it?” inquired his companion.

“Live in it!  I should say we were.  It is three times as big as the shack we had planned to build.  I can’t understand why two men like those fellows should have put up such a large cabin.  What do you think, Mukoki?”

Mukoki shook his head.  Evidently the mystery of the whole thing, beyond the fact that the tenants of the cabin had killed themselves in battle, was beyond his comprehension.

The winter outfit was soon in a heap beside the cabin door.

“Now for cleaning up,” announced Wabi cheerfully.  “Muky, you lend me a hand with the bones, will you?  Rod can nose around and fetch out anything he likes.”

This assignment just suited Rod’s curiosity.  He was now worked up to a feverish pitch of expectancy.  Might he not discover some clue that would lead to a solution of the mystery?

One question alone seemed to ring incessantly in his head.  Why had they fought? Why had they fought?