In the film, the Fantastic Four—Reed Richards (Mr. Fantastic), Sue Storm (Invisible Woman), Johnny Storm (Human Torch), and Ben Grimm (The Thing)—face a new challenge when a mysterious interstellar visitor, the Silver Surfer, arrives on Earth. The Silver Surfer heralds the arrival of Galactus, a cosmic entity that consumes planets to sustain its life force. The arrival of the Silver Surfer creates global panic as he travels across Earth, leaving destruction in his wake. The Fantastic Four must unravel the enigma of the Silver Surfer and confront this threat to Earth's existence. Their mission becomes personal as they deal with their own struggles, particularly Reed and Sue, who are attempting to balance their superhero responsibilities with their upcoming wedding.

As they pursue the Silver Surfer, the Fantastic Four discovers that there's more to their adversary than meets the eye, revealing a complex character with deep motivations. Their investigation leads them into conflict not only with the Silver Surfer but also with the U.S. military and their old nemesis, Victor Von Doom, who has his own agenda regarding the cosmic visitor and the impending doom. The team must overcome internal strife and external challenges to understand the true nature of the threat they face, setting the stage for a confrontation that will require them to unite and tap into strengths they never knew they had.