The full story
The Amazing Spider-Man 2 opens with a flashback: Richard Parker, fleeing Oscorp assassins on a private plane, uploads his research to a hidden server before the plane goes down. His secret: he genetically coded Oscorp's experimental spiders to bond only with Parker DNA. Peter is the only person who could have safely gained spider powers—it was never random.
In the present, Peter is a confident, acrobatic Spider-Man, beloved by New York. But he's haunted by visions of Captain Stacy—the promise he broke—and keeps pulling away from Gwen, then pulling her back. Their chemistry is electric but shadowed by guilt. Gwen, the valedictorian, has her own ambitions and refuses to be someone Peter protects by abandoning.
Max Dillon is an invisible man. A socially isolated, overlooked Oscorp electrical engineer whose own mother forgets his birthday. Spider-Man saves him once and Max becomes obsessed—his only experience of being seen. When an accident at Oscorp sends Max falling into a tank of genetically modified electric eels, he absorbs their bioelectric charge and transforms into Electro, a being of pure living electricity with translucent blue skin.
Electro's first public appearance in Times Square turns from confused plea to violent rampage when he feels ignored and rejected again—even by Spider-Man, who can't remember his name. Electro becomes a citywide threat, causing blackouts and destruction.
Harry Osborn returns to New York to inherit Oscorp after his father Norman's death. Harry is dying of the same hereditary genetic disease—Retroviral Hypodysplasia—that killed Norman. Believing Spider-Man's radioactive blood could cure him, Harry begs Peter (not knowing he's Spider-Man) to arrange a meeting. Peter refuses, fearing his blood could make Harry worse, like it did Connors. Harry, desperate and betrayed, breaks into Oscorp's restricted vault. He injects himself with an experimental Goblin serum that arrests the disease but transforms him into a monstrous Green Goblin with enhanced strength and a weaponized glider.
The climax converges at a power plant. Spider-Man and Gwen work together to defeat Electro using an overload strategy, restoring the city's power. But Harry arrives as the Goblin, deduces that Peter is Spider-Man because of his connection to Gwen, and kidnaps her.
The battle moves to a clock tower. Gwen falls. Peter fires a web that catches her—but the elastic snap of the webline doesn't arrest her momentum in time. Gwen hits the ground. She is dead. The clock face reads 1:21, a reference to Amazing Spider-Man comic issue #121, "The Night Gwen Stacy Died."
Peter is destroyed. He quits being Spider-Man for months, visiting Gwen's grave through seasons of weather changes. The city suffers without him.
Eventually, Peter replays Gwen's graduation speech—about hope, about not giving up, about the choice to keep going—and puts the suit back on. The film ends with Spider-Man confronting Aleksei Sytsevich (the Rhino) in a mechanized suit, charging directly at a threat, choosing to be the hero despite everything he's lost.
The film's end-credits tease Sinister Six members—Vulture and Doc Ock equipment visible in Oscorp's vault—but the franchise was cancelled before any sequels materialized.