Plot
Dr. Reed Richards (Ioan Gruffudd), a genius but timid and bankrupt physicist, is convinced that evolution was triggered millions of years ago on Earth by clouds of cosmic energy in space, and has calculated that one of these clouds is soon going to pass near Earth. Together with his friend, the gruff yet gentle astronaut Ben Grimm (Michael Chiklis), Reed convinces Dr. Victor von Doom (Julian McMahon), once his classmate at MIT and now CEO of Von Doom Industries, to allow him access to his privately owned space station to test the effects of exposure to the cloud on biological samples. Doom agrees, in exchange for control over the experiment and a majority of the profits from whatever benefits it brings. He brings aboard his beautiful chief genetics researcher (and Reed's ex-girlfriend from MIT) Susan Storm (Jessica Alba), and her hot-headed brother Johnny Storm (Chris Evans), a private astronaut who was Ben's subordinate at NASA but is now his superior on the mission.

The quintet travels to outer space to observe the cosmic energy clouds, but Reed has miscalculated and the clouds materialize well ahead of schedule. Reed, Susan, and Johnny leave the shielded station to rescue Ben while he has gone on a spacewalk to place the samples, and Victor closes the shield behind them. Ben receives full exposure in outer space, while the others receive a more limited dose within the station. They return home but soon begin to develop strange superpowers. Reed is able to stretch his body like rubber, Susan can become invisible and also generate impact resistant force shields, especially when she is angry. Johnny can engulf himself in fire at temperatures in excess of 4000 kelvins (erroneously described as being like a supernova in this film), and he is also able to fly unaided. Ben is transformed into a large, rocklike creature with superhuman strengths and durability.

Meanwhile, Victor faces a backlash from his stockholders because of the publicity from the space mission, and he has a scar on his face that came from an exploding control console that he was close to during the passage of the cloud.

Ben returns home to see Debbie, (Laurie Holden), his fiancee, but she cannot handle his new appearance and she runs away. Ben goes to brood on the Brooklyn Bridge, and there he accidentally causes a traffic pileup while he was stopping a man from jumping off the bridge. These four people use their various abilities to contain the damage and to prevent anyone from being hurt. While the public cheers them for their efforts, Ben sees his fiancee leave her engagement ring on the ground and leave him behind. Reed hands a heartbroken Ben the ring and vows to find a way to turn him back to normal. The media dubs them "The Fantastic Four" for their heroic deeds.

Victor watches the news story and he is told that his company is lost now, with the fame of The Fantastic Four overriding his company's downfall. All of the members of The Fantastic Four move into Reed's lab in the Baxter Building to study their abilities and to find a way to return Ben to normal. Victor offers his support in their efforts but he blames Reed for the failure of the spaceflight, the lights flickering as he grows enraged.

Victor goes to the Von Doom building and steals a heatseeking missile, and also a supercooling unit. Reed tells the group he will construct a machine to recreate the storm and reverse its effect on their bodies, but warns it could possibly accelerate them instead. Meanwhile Victor continues to mutate, his arm turning into an organic metal and allowing him to produce bolts of electricity, and he begins plotting to use his ability to take his revenge. Victor drives a wedge between Ben and Reed by telling Ben that Reed has no desire to change himself back, as the group's research has allowed him to rekindle his relationship with Susan. Reed and Ben argue, Ben walking out in a rage. This motivates Reed to attempt the machine on himself, but he cannot generate the power needed to push the storm to critical mass. Doom hears Reed tell Susan this through security cameras and has Ben brought to the lab. Ben is placed in the machine and Doom uses his abilities to produce the electricity needed to power it, turning Ben back to normal and accelerating Doom's condition, causing much of his body to turn to metal. Victor knocks the human Ben unconscious and captures Reed.

Victor - now calling himself "Doctor Doom" - puts on a metallic mask to hide his facial disfigurement, and then incapacitates and tortures Reed by using the supercooling unit. Doom fires the heatseeking missile at the Baxter Building in an attempt to defeat Johnny, but Johnny flies through the city to evade it, and then setting a large garbage barge on fire to trick it. Susan rushes to confront Doom as Ben begins to regret his decision to turn normal. Susan attempts to release Reed and battles Doom but is outmatched - Ben arrives to assist her, transformed into The Thing again by reusing the machine (speaking his signature line, "It's Clobberin' Time"). The battle spills into the streets, and the four assemble to battle Doom. Johnny and Susan combine their powers to wrap Doom in an inferno of intense heat, and Ben and Reed douse him with cold water, inducing thermal shock and freezing Doom in place. As an epilogue, Ben informs Reed that he has accepted his condition with the help of Alicia Masters, a blind artist for whom he has developed warm feelings, and the team decides to embrace their roles as superheroes and unite officially as the "Fantastic Four". Reed proposes marriage to Susan, who accepts and they share a kiss. Meanwhile, Doom's statuesque remains are being transported back to his homeland of Latveria when the dockmaster's electronic manifest briefly undergoes electromagnetic interference, suggesting that Dr. Doom is still alive.

Box office
In paid attendance, Fantastic Four was a commercial success, and it achieved the top position in gross income with about $56,061,500 collected during its first weekend. By September 2005, the Fantastic Four had accumulated a gross income of about $330,579,700 from theaters around the world, about $154,696,080 of this coming in the United States.

Critical response
Fantastic Four received unfavorable reviews from critics and audiences. This movie scored only a 27% rating at the aggregate critics' Web site Rotten Tomatoes and 40 out of 100 at Metacritic.