Days of Future Past asks whether the past can be changed, or whether some futures are inevitable. It is a film about destiny, responsibility, and the burden of knowledge.
The film opens in a hellscape. Mutants are nearly extinct, hunted by sentinels—robots designed to identify and eliminate them. Xavier and Magneto, separated by decades of enmity, reunite to send Wolverine's consciousness back fifty years with a single mission: stop Mystique from assassinating Bolivar Trask, the scientist whose death will inspire the creation of sentinels that will eventually eliminate all mutants.
This is the paradox at the film's heart: Mystique must be stopped from committing murder. But Mystique believes she is committing an act of justice. Trask has engineered anti-mutant weapons. From her perspective, killing him is preventing genocide. From Xavier's perspective, killing him accelerates the very thing it claims to prevent. The film presents both views as having moral weight. Mystique is not wrong to see Trask as a threat. Xavier is not wrong to believe that mutant-on-human violence will trigger backlash. They are both responding rationally to the world as they understand it, and their rationality leads them to irreconcilable conclusions.
The narrative threads past and future together. In the past, young Xavier is broken—his legs shattered, his belief in humanity erased. Young Magneto is imprisoned, convinced that mutants cannot coexist with humans. Wolverine must bring them together not because they want to work together, but because the alternative is annihilation. He must convince them to change history by preventing a murder and by saving the life of a man who will hunt them.
The complexity emerges when Mystique realizes that Wolverine is from the future and that her actions lead to extinction. The film does not resolve this easily. Knowing the consequences does not make Mystique want to spare Trask. She wants to protect her species. She believes Trask is an existential threat. Knowing that his death creates sentinels does not convince her that his life is preferable.
The climax involves Mystique's choice: she can kill Trask and accept that this act will eventually lead to genocide, or she can spare him and accept that he will continue his work. She chooses to spare him not because she has been convinced of Xavier's pacifism, but because she recognizes that historical causality is complex. She cannot know with certainty that her actions will cause the future she wants to prevent. In the face of that uncertainty, she chooses mercy.
But the film's ending is ambiguous. Wolverine returns to a future that has changed, but not become paradisiacal. Mutants still exist, but the threat remains. The future is not erased; it is altered. Some problems are prevented; new ones emerge. The film understands that changing history does not eliminate struggle. It only redirects it. The question that lingers is whether this new future is better or simply different. The answer is left to the viewer's interpretation, which is precisely where the film's wisdom lies.