The Four Stragglers. Frank L. Packard

"The Four Stragglers" opens in the darkness of an unnamed battlefield during the Great War. Cut off from their respective units, three soldiers take refuge in a thicket; a fourth lies dead or unconscious a few metres away. Flares flying above reveal faces, and the cognizant come to recognize that they'd all played parts in a daring jewel heist not two years earlier.