Spider-Man 3 - Plot

Plot

Peter Parker plans to propose to Mary Jane Watson, who has just made her Broadway musical debut. Meanwhile, a small meteorite crashes near the two in Central Park, and an extraterrestrial symbiote attaches itself to Peter's moped. Elsewhere, police pursue escaped prisoner Flint Marko. He breaks into the site of an experimental particle accelerator, which fuses his body with the surrounding sand and allows him to shapeshift at will as the Sandman.

Peter's best friend, Harry Osborn, who knows Peter is Spider-Man and believes that Peter is responsible for his father Norman Osborn's death, attacks Peter using new weapons based on his father's Green Goblin technology. Harry injures his head on a pipe and suffers from partial amnesia, making him forget his revenge and that Peter is Spider-Man.

During a festival honoring Spider-Man, Marko robs an armored car. NYPD Captain George Stacy, Gwen's father, tells Peter and Aunt May that Marko was Ben Parker's killer, and the deceased Dennis Carradine only an accomplice. While a vengeance-obsessed Peter sleeps, the symbiote bonds with him. Peter wakes up hanging from a skyscraper and discovers his costume has changed and his powers have been enhanced. But the symbiote brings out Peter's dark side. Wearing the new black suit, Spider-Man locates Marko and fights him in a subway tunnel. He discovers water is Marko's weakness and uses a water pipe to reduce the Sandman to mud.

Peter's changed personality alienates Mary Jane, whose career is floundering, and she finds solace with Harry. Harry recovers from his amnesia after being urged on by a hallucination of his dead father with touching the mirror, compels Mary Jane to break up with Peter. After Mary Jane tells Peter she loves somebody else, Harry meets with Peter and claims to be "the other guy". Later, Peter, wearing the black suit, confronts Harry and after a brutal fight, spitefully tells him his father never loved him. Harry throws a pumpkin bomb at Peter, who deflects it back, disfiguring Harry's face.

Under the symbiote's influence, Peter exposes Eddie Brock, a rival photographer at the Daily Bugle, for submitting doctored photographs showing Spider-Man as a criminal. Furious at having to print a retraction, J. Jonah Jameson fires Eddie. Meanwhile, the Sandman recovers from his injuries.

To make Mary Jane jealous, Peter brings Gwen to the nightclub where Mary Jane works. Gwen catches on and storms out. Peter gets into a fight with the bouncers and after accidentally hitting Mary Jane, he realizes the symbiote is changing him. Retreating to a church bell tower, he finds he cannot remove the suit. But the alien weakens as the church bells ring. Peter tears the symbiote off and it falls to the lower tower, landing on Brock, who is praying for Peter's death. The symbiote attaches to him and Brock, transformed into Venom, finds the Sandman and offers to join forces.

Brock hijacks Mary Jane's taxi cab and hangs it from a web hundreds of feet above a sand-filled construction site. Peter seeks Harry's help, to no avail. Harry later learns the truth about his father's death and decides to help Peter. Harry temporarily subdues a gigantic incarnation of the Sandman while Brock tries to impale Peter with Harry's glider. Harry jumps in the way and is stabbed instead. Fighting the symbiote, Peter recalls how the church bells weakened it. He grabs pipes and creates a ring around the symbiote, creating a wall of sonic vibrations. The alien releases Brock, and Peter uses his webbing to pull Brock from the creature. However, the symbiote, having gained more than enough power from Peter and Brock, is capable to live on its own without a host. Peter throws a pumpkin bomb at the symbiote, but Brock jumps in to rebond with it, and both are destroyed by the blast.

Marko tells Peter he never intended to kill his uncle, but only wanted his car and shot him by accident when Dennis grabbed his arm. He claims Ben's death has haunted him since. Peter forgives Marko, who dissipates and floats away. Peter and Harry forgive each other, and Harry dies with Mary Jane and Peter at his side. Days later, Peter visits the jazz bar where Mary Jane is singing, and they dance.