Moffitt gets seriously wounded during a raid on a German convoy with the Rat Patrol far behind enemy lines. So Troy decides to obtain blood from a nearby German field camp. Dietrich is in charge of the base; Troy encounters him and orders him to help him find a donor. Dietrich sends for Corporal Pennell, a captured American deserter. Pennell refuses to cooperate, but Troy takes him at gunpoint. On the way back to Moffitt, Dietrich catches up to them, and Pennell must do the "impossible" to prevent them from all being recaptured. He rises to the occasion, and they make it back to Moffitt and Tully in time to save Moffitt's life. As for Pennell's future, Troy will say the corporal was, unfortunately, separated from his unit by accident.