A Sound of Thunder (film) - Plot

Plot

In the year 2055, time travel (referred to as "time jumping") is possible, but the process is dangerous and unpredictable. Charles Hatton (Ben Kingsley) creates a "Time Safari" service, offering the opportunity for wealthy clients to travel to prehistoric days and hunt dinosaurs. The expedition, led by Travis Ryer (Edward Burns), is set under very specific rules to avoid altering history: their targets are a set of dinosaurs that will imminently be killed by lava from an erupting volcano, frozen nitrogen bullets are used as ammo to leave no trace, and the party wears self-contained suits and told to stay on a floating path and to not touch anything. Further, all the guns are tied to Travis Ryer's weapon, and will not fire until he does so.

The team is initially led by Travis Ryer, along with Jenny Krase, Payne, Clay Derris, Dr.Lucas. Their guests Alicia Wallenbeck and John Wallenbeck join the Expedition. When they successfully complete the expedition and return to the future, Charles Hatton organizes a Party to celebrate the success of the first expedition. The party is interrupted by Sonia Rand, who tosses red wine on Alicia, John and Charles. Sonia is one of the inventors of the time machine but voted against making it a business. She is later confronted by Travis and the two have a brief conversation in Sonia's Lab, Sonia explains to him the danger of using the time machine.

During another trip while escorting clients Eckles (William Armstrong) and Middleton (Corey Johnson), Ryer's gun fails as their target Allosaurus rushes the party. Ryer tells the tourists to take cover while he corrects the weapon in time to kill the Allosaurus. Ryer removes traces of their presence and quickly takes the tourists back to the present, unaware that Middleton has accidentally stepped off the path while taking cover. After the second expedition, Alicia sleeps with Travis. Then, news is aired on TV, which describes rapid changes in the environment, as Travis looks at a small plant that is now large and wild. On a subsequent trip to the same point in time with a different group, Ryer is shocked to find that events have changed as the Allosaurus is already dead and the volcano has erupted too soon.

When Ryer returns to report this, "Time Safari" is immediately shut down by the federal agency that oversees time travel technology. Just as Ryer is in a taxi cab, the road collapses, leading some cars to go under it and people start panicking. Ryer seeks out Sonia Rand (Catherine McCormack), the inventor of the time travel technology. Rand had long had reservations about "Time Safari", and worries that events will play out as she had predicted. Suddenly, the two feel themselves caught in a wave front, which Rand later identifies as a time wave that is a result of the changes in the past. It causes the vegetation and animal life in her greenhouse to grow rapidly and dangerously. They heard a woman screaming knocking at the door and Sonia opens it as they encounter a swarm of large type beetles. The woman falls dead on the floor. They panic, Travis gets the water hose and electrocutes the insects causing a large explosion, forcing the two to evacuate. Rand warns several more time waves can be expected, each affecting more advanced parts of life and, eventually, humans themselves.

Returning to Time Safari, the federal agency works with Ryer and Hatton to send Ryer back to the past to try and correct it. Instead, Ryer appears in the American Southwest during the 18th century; he quickly returns to the present time as another time wave hits, it knocks down the power out from the building and leaving the city covered in dense vegetation.They decided to took over the events, the team's technician Payne (David Oyelowo) discovers that one of the tourists on the earlier expedition came back from the past one gram heavier. Though such discrepancies would have been found with the required "bio-filter" on their return, Hatton had paid off a federal agent to avoid the costly process. The small team including Travis, Sonia, Payne, Clay and Jenny head outside to find out what's going on, but Payne is bitten by a strange poisonous plant. As the group walks, they encounter an ape like dinosaur creature that attacks Clay but Travis saves him by shooting the creature. Just as they flee, a large group of creatures follow them and, since Payne is dying, he offers himself to the creatures so that the team can escape. They track down Eckles first and find a group of survivors barricading themselves in a building where Travis saves a man and his son in a grocery store from the ape-like creatures. They find Eckles but it seems he did not do anything. So they track down Middleton. As they entered the building they find a man with a gun, but Middleton shoots him and threatens to shoot Travis, but Travis shoots him. They confirm that Middleton had stepped off the path, crushing a butterfly and thus altered history.

When another time wave completely severes power to the Time Safari time portal, the group realizes the only option is to travel to the nearby university to use its particle accelerator like a time machine to send someone back to intercept the original expedition and prevent Middleton from stepping off the path. Travis, Sonia, Jenny And Clay travel to the Main Laboratory, but just as they are on the road, bat like creatures attack them and kill Clay. As another time wave appears, the car loses control and hits a building. They get out and find that Charles and members of the crew are dead. They also find Dr. Lucas hiding. Travis convinces Dr. Lucas to come with them but he refuses. As soon as the team gets out, he changes his mind and follows them but is too late, the ape like creatures appear and kill him. The group then decides to use the underground railway because its safer, but to make matters worse it turned into a swamp. As they get inside a train, the ceiling of the tunnel collapses, flooding it and the three are trapped inside. The water floods the train and Travis decides to blow the window so they can escape. While they are escaping, a long dragon fish like creature appears and devours Jenny, forcing Travis and Sonia escape, but as they escape the creature grabs hold Travis and is ready to devour him. The ceiling of the tunnel then fully collapses trapping and killing the creature with the debris. Sonia helps Travis and they arrive at the University while the ape like creatures followed them. Sonia is able to make the modifications and send Ryer back in time just as a time wave hits, leaving her as catfish-like humanoid.

In the prehistoric path, Ryer successfully intercepts the hunting party while handing over a video recording to Jenny, with the group returning immediately to the future, this future version of Ryer disappears. Back in the present, Travis confronts Charles to stop the expeditions, as Jenny gives him the video that future-Travis gave her and kisses present-Travis. Ryer watches the video tape by himself, and takes it to Rand. They agree that the video contains enough evidence to put an end to Time Safari.