Full story
A silver object streaks across Earth's skies, leaving giant craters, blackouts and wild weather wherever it goes. The government asks Reed Richards for help, but he is busy with something else: his wedding to Sue Storm, which has been pushed back several times. They both promise that this time nothing will get in the way.
Of course something does. In the middle of the ceremony in New York, the object passes over the city and knocks out the power. Johnny Storm flies after it and finds a silver humanoid riding a board, soon nicknamed the Silver Surfer. The encounter is rough and Johnny falls out of the sky. Afterward he discovers a weird side effect: whenever he touches a teammate, they swap powers. Reed tracks the Surfer's energy and sees that whole planets died soon after his visits. The next target is London, where the team fails to stop another crater.
In Latveria, the Surfer's pass revives Victor von Doom, stuck in a metal shell since their last fight, and restores his human form. Doom tries to team up with the Surfer, gets turned down and blasted, but soaks up some of that energy. The military forces the Fantastic Four to work with Doom. Reed builds a pulse that separates the Surfer from his board, and he is captured in the Black Forest. In custody, he tells Sue the truth: he serves Galactus, a being that devours planets, and took the job to save his own world and the woman he loved.
Doom betrays everyone, steals the board and becomes a threat with cosmic power. Sue frees the Surfer and the team chases Doom to Shanghai. In the fight, Sue is impaled by an energy spear while shielding the Surfer. Johnny absorbs all four teammates' powers at once, beats Doom and gets the board back.
Galactus is already arriving, a huge cloud filling the sky. The Surfer reclaims his board, brings Sue back to life with his energy and flies straight into Galactus. A massive blast seems to destroy them both. Reed and Sue finally get married in a quick ceremony in Japan. In the mid-credits scene, the Surfer floats in space with his eyes closed. The board flies back to him and his eyes open. His fate is left open.