In the exposition, Ekles walks into Time Safari, INC. He wants to go back 65 million years ago to kill a T-rex. The man tries to scare him, and it worked. Ekles still wants to go, so they prep him and send m back.
When they get to the past Travis tells Ekles and others the rules. The most important rule is to NEVER STEP OFF THE PATH! The dinosaur comes and there are complications and Ekles gets scared and falls off the path. Travis gets mad and sends him to retrieve the bullets. They go back to the present.
When they got back to the present and notice the exact same sign but it was different. Meaning that when Ekels fell off the path he casused the future to change. When Travis notices he puts his gun to Ekels head and kills him.