High-school senior Peter Parker lives with his Aunt May and Uncle Ben, and is a school outcast and bully victim. On a school field trip, he visits a genetics laboratory with his friend Harry Osborn and unwitting love interest Mary Jane Watson. There, Peter is bitten by a genetically engineered super spider. Shortly after arriving home, he becomes ill and falls unconscious. Meanwhile, Harry’s father, scientist Norman Osborn, owner of Oscorp, is trying to secure an important military weapons contract. He experiments on himself with an unstable performance-enhancing chemical. After absorbing the chemical, he goes insane, kills his assistant, and destroys the laboratory.
The next morning, Peter finds that he is no longer near-sighted, and his body has metamorphosized into a more muscular physique. At school, he finds that his body can produce webs from the wrists, and his quickened reflexes let him avoid injury during a confrontation with Flash Thompson. Peter discovers he has developed superhuman speed, strength, the ability to stick to surfaces, and a heightened ability to sense danger.