That thrilling cry haunted him.

The frantic flight of an Indian brave--nay, of a cunning, experienced chief--was not to be lightly considered.

The savages were at home in these untracked wilds.
Trained from infancy to scent danger and to fight when they had an equal chance they surely would not run without good cause.
Joe knew that something moved under those dark trees.

He had no idea what.

It might be the fretting night wind, or a stealthy, prowling, soft-footed beast, or a savage alien to these wild Indians, and wilder than they by far.