Full Metal Jacket begins by following the trials and tribulations of a platoon of fresh Marine Corps recruits focusing on the relationship between Gunnery Sergeant Hartman and Privates Pyle and Joker. We see Pyle grow into an instrument of death as Hartman has foreseen of all of his recruits. Through Pyle's torment and Joker's unwillingness to stand up against it the climax of part one is achieved with all three main characters deciding their fates by their action or inaction.
The second chapter of Full Metal Jacket delves into Joker's psyche and the repeated referral to the fact that he joined the Corps to become a killer. When his mostly behind the scenes job as a combat correspondent is interfered with by the Tet offensive he is thrust into real combat and ultimately must choose if he really is a killer.