"Sand Castle" tells a story adapted from a true story, based on an Iraq War. 19-year-old soldier Matt Ocre (Nicholas Hoult) and his platoon leader, Sergeant Baker, were ordered to protect a remote and dangerous village, Baquba, to repair important pipelines. Because of this mission, they became targets of enemy forces, sniper attacks, suicide bombers, and they had to be constantly vigilant. As the days passed, his comrades were sacrificed, and Matt's willpower was slowly being worn away, making him face the darkest part of himself.