Complex sentence: Involuntarily, Lefort and Bouvet get themselves tangled up in the manhunt against the aviators led by Wehrmacht Major Aschbach as they help the airmen to go back to England with the help of Resistance fighters and sympathizers.
Split into simpler sentences: Involuntarily, Lefort and Bouvet get themselves involved in the manhunt against the aviators led by Wehrmacht Major Aschbach. They have to help the airmen to go back to England with the help of Resistance fighters and sympathizers.