There swept over him an irrepressible

  Yet, insisted the Inspector, the halfbreed was not rustling. Mahon gave it up.   Ahead of him loomed the dark line of the beloved Hills, swelling as he cantered along. Over the yellow glare of the dead prairie grass his eyes rested on the deep green with the affection of a long-absent friend. There swept over him an irrepressible longing to dash into the cool shadows and feast his eyes on the maze of hill and dell, rocky height and grass-grown bottom, mirrored lake and whispering stream; to hear the leap of fish and the rustle of creeping things unseen, the cry of distant birds and the howl of prowling wolf. There he would be in touch with the spirit of his old friend, wherever he might be now.   Some day--he felt certain of it--he would grasp the hand of Blue Pete somewhere within the Hills.   Constable Priest was not at the post when he pushed open the barracks door. He was glad of that. Leaving a short note, he galloped off south-east toward the Hills. His horse, with memories of many a free run there, made straight for Windy Coulee, the familiar western entrance to the mysteries of the Cypress Hills.   Mahon did not direct. When the sloping trail leading up into the trees rose before him, he smiled. With Windy Coulee the halfbreed's memory was bound by a hundred incidents. There they had entered their first great adventure together; there they had dived into the shadows on the trail of many a rustler. And there he had erected the rough stone that marked his grief when he thought Blue Pete had given his life for him.   Wrapped in the past, Mahon gave the horse his head.