grab the tissues this one is a tear jerkier for sure if your a pet lover
Max, used to help U.S. Marines in Afghanistan, is handled by Kyle Wincott. Kyle is questioned when weapons seized by his squad go missing. Realizing his friend Tyler Harne is among those involved with the shady dealings, he warns Tyler that he cannot cover for him. The two then go into the battlefield with their squad, with Max on point. While advancing on a suicide bomber, Max is injured by an explosion. In the ensuing gunfight, Kyle is shot and killed.
Kyle's younger brother Justin, who makes money selling illegally copied video games, their mother Pamela and their father Ray are informed of his death. After Kyle's body is brought home for burial, the other Marines notice that Max is only calm when he is around Justin, apparently sensing that he is Kyle's brother. The family adopts the dog, who would otherwise be euthanized for his disturbed behavior. Justin initially wants little to do with Max but eventually warms up to him. While meeting up with his friend Chuy, Justin meets Chuy's cousin Carmen, who offers to go to his house and show him some handling tricks for Max. Little by little, Max's behavior improves around other people.
Tyler visits the Wincotts one evening, provoking an aggressive response by Max. When asked by Ray on what really happened to Kyle, Tyler implies that Max turned on Kyle and caused him to discharge his weapon on himself, leading to his death. Justin decides to investigate the matter. Calling on one of Kyle's old friends, Sergeant Reyes, for help, he is given a DVD of Kyle training Max that moves him to tears.
Later, Justin is approached by Chuy's other cousin Emilio, a cartel member, who presses him over a video game bootleg. Afterwards, Justin and Max follow Emilio into the woods, where they secretly observe a meeting between cartel members and Tyler, who tries selling stolen weapons to them. The cartel's dogs sense Max and run after him. Max fights them off, severely wounding one of the dogs, while Justin runs away and leaves his bike behind. When he gets home, he finds Tyler and Stack, the cartel's dog handler, who was injured in the melee. Feigning innocence, they accuse Max of doing harm and demand his euthanization.
Max is taken by animal control officers but escapes. Meanwhile, Ray catches Tyler making a business deal with the cartel but is held hostage by Emilio. Max makes it home and leads Justin, Chuy, and Carmen into the woods to rescue Ray. Confronting the cartel, they incapacitate Emilio and the last cartel dog and rescue Ray. Tyler and Stack chase after Justin and Ray, but Stack is killed after crashing his off-road pickup truck. Tyler corners Justin at a damaged bridge, but is attacked by Max. The two are knocked over the side of the bridge; while Tyler is killed by the fall, Max survives.