The story revolves around a fur trapper from the early 19th century named Hugh Glass (very convincingly played by Leonardo DiCaprio). After being nearly killed by a bear protecting its cubs (in the mauling referenced above), Glass is bandaged up and then carried on a crudely constructed litter through miles and miles of rugged country in the middle of winter. So sick is he and such an encumbrance to his colleagues that many in the party wonder whether it might be better simply to kill him. But Glass's son, a half-white, half-Indian teenager named Hawk, vigorously defends his father. Eventually, however, Fitzgerald, one of the strongest advocates for eliminating Glass, makes his move, murdering Hawk in cold blood and placing Glass in a shallow grave, convinced that the profoundly injured man would never manage to extricate himself.
But in the first of a number of resurrection/re-birth scenes, Glass crawls out of his grave and despite his appalling injuries manages to make his way. What follows is like something out of Dante's Inferno or the book of Job. When he tries to take a drink, the water runs out of the wounds in his neck; when he seeks shelter in a cave, Indians find him and he is compelled to escape down a fast-flowing stream while arrows whiz by his head; when we think he is relatively safe, he is attacked again and forced to escape on horseback right over a steep cliff, killing the animal and leaving himself even more grievously injured; exposed to lethal cold, he eviscerates the horse and sleeps in the confines of the carcass, etc., etc.
What is driving him during this entire ordeal is a burning desire for vengeance against Fitzgerald, the man who killed his son and left Glass himself for dead. He will face down every obstacle and withstand any assault so that he might bring this wicked person to justice. In this, he comes to imitate the bear with whom he had grappled to the death. Throughout the central section of the film, Glass is clad head to toe in furs, shuffles and grunts his way through the wilderness, eats animals and fish raw. He has become the grizzly, roused to fury because of an attack on his offspring.
The pivotal moment of the film occurs when, at the end of his strength, Glass encounters a Pawnee warrior who feeds him and shelters him during a ferocious storm. In conversation afterward, Glass learns that his benefactor had himself lost his entire family at the hands of white settlers. Filled understandably with rage and a desire for vengeance, the Indian concluded, nevertheless, that "vengeance is best left to the Creator." In a dream/fantasy sequence just after this conversation, Glass finds himself in the midst of the ruins of a Christian church, where he spies and embraces Hawk, reaching out, as it were, across the divide to a transcendent world, where the Creator rules. Without giving away too much more of the plot, suffice it to say that Glass tracks down Fitzgerald and engages in mano a mano combat with him until he remembers what the Pawnee had said and allows his wounded counterpart to drift down the river.
The film carries a crucially important message, especially for our secularist time, namely, that, as Evelyn Waugh put it in Brideshead Revisited, "the supernatural is the real." The Revenant is unremittingly honest in its portrayal of people caught in the awful reality of this fallen world, which is marked through and through by violence, suspicion, hatred, revenge, and the constant struggle to survive in the context of an indifferent nature. For the denizens of this universe, the correct mottos are indeed "kill or be killed" and "love your friends but hate your enemies" and "an eye for an eye and a tooth for a tooth." If there is no God, as Fitzgerald suggests to one of his underlings, survival at any cost, the law of the jungle, is the supreme law. But if there is a dimension that transcends nature, if there is a God who provides a moral compass and presides over human affairs, then one can let go of vengeance and seek a higher justice. The film ends just as this consciousness of God dawns on Glass.
How much of human history has been dominated by revenge which produces an endless cycle of violence? And how present is this dynamic in the struggles of today: Muslim factionalism in the Middle East, anti-Christian violence in Africa, terrorism everywhere? Nothing within fallen nature will ever break us free of these cycles. Only an openness to the transcendent God, a higher power to whom we can entrust our thirst for justice, will solve the problem that most bedevils the human heart. The slowly-dawning awareness of this truth is the greatest re-birth undergone by Hugh Glass, and watching it happen is a very good reason to see The Revenant.