A Sound of Thunder rising action?

In Ray Bradbury's "A Sound of Thunder", the rising action begins when Eckels, the main character, decides to travel back in time with a group of other tourists to hunt dinosaurs. The tension builds as Eckels is confronted with the moral dilemma of whether or not he should kill a butterfly during his hunt, which could have disastrous consequences for the future. Despite warnings from his guide, Travis, Eckels is unable to resist the temptation and steps off the designated path to kill the butterfly. This sets in motion a chain of events that culminates in Eckels returning to the future only to find that everything has changed due to his interference in the past.