In the climax of the movie, Dan Forester and his team manage to secure the toxin from a captured White Spike. However, things take a turn when they discover that the toxin alone is not enough to defeat the aliens. To save humanity, Dan realizes they need to go back even further in time to the prehistoric era, where the White Spikes originated, and obtain a pure form of the toxin.
Dan, his estranged father, and a select group of soldiers embark on this dangerous mission. They face numerous challenges in the past, including confrontations with the deadly creatures. During these sequences, there are sacrifices, and characters from the team lose their lives.
Eventually, Dan successfully acquires the pure toxin and returns to the present. The toxin is developed into a potent biological weapon that can wipe out the White Spikes. In a final battle, the remaining human forces use this weapon to decimate the alien threat.
The movie ends with humanity saved from the immediate danger, and Dan returns to his own time. However, there are hints that the consequences of time travel might have lingering effects. Dan decides to make the most of the time he has with his family, recognizing the importance of the present.
As for the future timeline, it is suggested that the world is now free from the alien invasion, but there are potential storylines left open for sequels or further exploration of the repercussions of time travel.