The Adventures of Young Indiana Jones: Trenches of Hell (1999)

In the eighth film in the series, in August 1916, using the name "Henri Defense," 17-year-old Indiana Jones has enlisted in the Belgian army to fight in the Great War. After his commanding officers have all been killed in battle in Flanders, Corporal "Defense" is left in charge of what's left of the 9th Belgian Infantry. They are assigned to the French 14th Company and dispatched into the Battle of the Somme. When Indy is captured by the Germans, he quickly gains a reputation as an escape artist, and is sent to the maximum security prison at Dusterstadt on the Danube.