When Billy gets back from his emergency trip home, he's immediately sent to Europe to fight the Germans in the Battle of the Bulge.
Billy never even gets to meet the new chaplain he's supposed to assist. He never gets a helmet or combat boots.
He somehow manages to get lost behind enemy lines.
He falls in with three other American soldiers (two scouts and an anti-tank gunner), none of whom have maps, food, or anything helpful.
Billy is the most pathetic of all: he is tall and skinny and without a helmet, overcoat, weapon, or boots. Even though he's only 21, he's going bald and his beard is coming in white.