Super 8 starts with Deputy Sheriff Jack Lamb (Kyle Chandler) and his son Joe (Joel Courtney) mourning the death of his wife.
Four months after Joe’s mother’s death, he is seen hanging out with his good friend Charles Kaznyk and the two decide to make a film that they will enter in an international film competition. They ask the help of their other friends in making the movie. One of their friends, Alice (Elle Fanning), seems to have something special going on with Joe.
Charles contemplates shooting a scene on the train station. As they are shooting, Joe catches with his camera the collision of a pickup truck with the incoming train. The train derails and the teenagers escape certain death by a hair. The kids check on the wreckage and they see box crates filled with strange white cubes. They also find out that the truck driver is no other than their biology teacher, Dr. Woodward. Woodward survives the accident and he threatens the children with a gun. He warns them not to tell anyone what they have seen. Just as the kids leave the train station, the U.S. Air Force, led by Col. Nelec, arrives and sets camp at the scene of the accident. Col. Nelec discovers evidence that the accident may have actually been caught on camera.
Joe and Charles agree to develop the film they used on the train station. While they wait, strange things start happening around town. Some people go missing and the animals run away. In addition, most electronic machines are being stolen. Joe hears some military gossip and he tries to get some help from Nelec but Nelec arrests him. The military purposely starts making wildfires to get people to evacuate. On the other hand, Joe and Charles see that their camera caught something coming out from the train wreckage.
Joe goes to the base and discovers that Alice is snatched by the creature from the train. Joe asks for the help of his friends again and together, they sneak into Dr. Woodward’s trailer where they discover evidence of the teacher’s job as a government researcher.
One of the films they discovered in the trailer shows that an alien craft has crash landed on earth in 1958. The alien on board was captured and experimented on by the military. Dr. Woodward was one of the scientists who investigated the extraterrestrial being. From the film, they also see that the space craft was made of white cubes. A scene shows the alien grabbing Woodward. This incidents psychically connected Woodward with the alien. Woodward was enlightened and he set about on saving the alien from the military forces. The train provided him with the opportunity to save the alien.
The military catches Joe and his friends in the trailer and they are taken to the base. The alien attacks while they are on their way to the base and the boys manage to escape. Joe’s father learns that his son plans to save Alice. Setting his beef with Alice’s father, Dainard, the two men make an alliance in order to save both of their children.
Joe and his friends make their way through the cemetery while the military engages in a battle with the alien. Some of the kids are injured on the ways and only Joe and Cary are left to carry out the mission to save Alice. They end up in an underground cavern where they discover an alien-made device created with the stolen electronic machines from all over town. They also see Alice and the other townspeople hanging unconscious on the ceiling of the caverns. Cary distracts the alien using a firecracker while Joe rescues Alice and the other hostages. The alien goes after them and catches Joe. Joe tries to persuade the alien to release him by telling the creature repeatedly that “bad things happen” and the creature “can still live.” The alien seems to understand and it lets them go free.
When they reach the surface, Joe and Alice are reunited with their parents. The people of the town then witness as the metals from the vicinity fly to the top of the water tower and white cubes take the form of a spaceship. The movies ends with the alien getting into the spaceship and the vehicles launches into the sky as the people around town watch.