Aporia

Eight months after Malcolm's death, Sophie is overwhelmed by grief and battling severe depression. Her relationship with her daughter Riley is strained, and she resents that Darby Brinkley has faced little legal consequence. Physicist Jabir Karim visits and reveals that he and Malcolm built a machine capable of sending a subatomic particle to the past, hinting at a possible way to alter the tragedy.

Sophie initially remains incredulous, but she agrees to test the device. They set a target to eliminate the accident by killing Darby in the past. The machine activates, and they are astonished to witness a new timeline in which Malcolm is alive; only Sophie and Jabir retain memory of the original timeline.

Sophie is overjoyed to have Malcolm back, but the new timeline brings subtle, unexpected changes to their lives. She begins to notice small differences that reveal the past was altered. The experience forces her to question whether changing history was the right choice.

Sophie and Jabir debate whether further meddling with time is acceptable. They consider erasing mass murders by preemptively targeting perpetrators, but the idea unnerves them. Sophie worries about the unpredictable consequences of altering memory and history.

Sophie learns that Darby's widow Kara and her daughter Aggie are destitute in the current timeline due to Darby's death. She befriends them and resolves to help them, hoping to mitigate the collateral damage caused by their changes. This realization deepens Sophie’s guilt over the havoc they have unleashed.

The trio agrees to use the machine to aid Kara and Aggie, including a plan to undo harm by eliminating a con man who had tricked Kara and cost her bakery. They believe their intervention could restore some stability to the family’s life. The decision demonstrates how personal histories can be rewritten through time travel.

After implementing the change, Kara and Aggie prosper, but Sophie and Malcolm discover their daughter no longer exists in this timeline. Instead, they have a son whose presence they cannot remember in the old reality. They realize it would be cruel to raise a child under a memory erased by time travel.

The group recognizes the machine has caused deep, unpredictable harm and chooses to end it by letting Jabir reset history. They decide that Jabir will use the device to save his own family, creating a timeline in which the machine was never built. Only Jabir would keep memories, while Sophie and Malcolm are emotionally rearranged to fit the new reality.

Jabir activates the machine alone, aware of the personal cost and the uncertain future. He hopes his action will repair the path for his family while leaving others to their new lives. Sophie and Malcolm awaken in a world where the device never existed, with memories altered to align with the new timeline.

In the new timeline, Sophie arrives home from work and enters the front door, greeted by a house that feels both familiar and strangely different. The film ends without revealing what is inside, leaving the audience to ponder what changed and what remains. The central questions about memory, responsibility, and the costs of changing the past linger unresolved.