The full story
The Amazing Spider-Man resets Spider-Man's origin with a different tone: darker, more grounded, and driven by the mystery of Peter Parker's parents. As a child, Peter is left with Uncle Ben and Aunt May after his father Richard Parker—an Oscorp geneticist—hastily hides his research and flees with Peter's mother. Both parents die in a plane crash.
Years later, teenage Peter finds his father's old briefcase containing a formula for cross-species genetics. It leads him to Oscorp and Dr. Curt Connors, Richard's former research partner, who lost an arm and has been trying to develop a regeneration serum using reptilian DNA. In Connors's lab, Peter is bitten by a genetically modified spider and gains superhuman abilities—but unlike the Raimi films, this Peter builds mechanical web-shooters rather than producing organic webs.
When Uncle Ben is killed by an armed robber Peter let escape—the guilt-driven origin repeated but reframed—Peter becomes a masked vigilante hunting criminals, eventually crafting the Spider-Man identity. He falls for Gwen Stacy, a classmate and Oscorp intern, whose father Captain George Stacy leads the NYPD and considers Spider-Man a dangerous vigilante.
Under pressure from Oscorp executive Rajit Ratha to rush human trials, Connors tests his regeneration serum on himself. It regrows his arm but mutates him into a massive reptilian creature—the Lizard. Initially horrified, Connors becomes consumed by a twisted philosophy: humanity is weak and flawed, and cross-species evolution is the next step. He plans to use Oscorp Tower's chemical dispersal device to aerosolize his serum over Manhattan, transforming the entire city into lizard-hybrids.
Gwen synthesizes an antidote while Peter races to the tower. In the climactic rooftop battle, Spider-Man swaps the serum for the antidote, dispersing a cure that reverts Connors and all affected people back to human. But during the fight, the Lizard fatally wounds Captain Stacy.
Dying, Captain Stacy makes Peter promise to stay away from Gwen—to keep her safe from the dangers that follow Spider-Man. Peter tearfully agrees.
He keeps the promise. Briefly. In the final scene, Peter shows up at Gwen's classroom, unable to stay away. She smiles knowingly. An English teacher quotes a line about promises being meant to be broken. Peter cannot protect Gwen and love her at the same time—but he's choosing love, and the audience knows this choice will have consequences.