o donnell: in louisiana, a desperate search for two missing sisters came to a happy end thanks in part to a good boy named artemis. cbs s david begnaud dug up the story. reporter: meet artemis, the bourg family pet, and their hero. when abigail and cecilia, age 7 and 4, went missing recently in the woods behind their louisiana home, artemis went with them. i just started, like, running around the whole property, six acres. that s when i called him and said, hey, they re gone. reporter: police and neighbors searched for hours. before i knew, it was past 9:00 and we still mad no word. near more than a mile the girls got tired and turned to artemis. she was hanging on his collar. really? yeah. reporter: four hours later, the searchers heard artemis bark