The full story
On his first day at a new high school, Peter Parker is bitten by a spider that emerges from one of Doctor Strange's interdimensional portals and starts developing powers he doesn't understand. He starts operating as a masked, self-taught vigilante while trying to keep up with school, his friend Nico Minoru, and a crush on classmate Pearl Pangan.
Norman Osborn figures out Peter's secret identity and recruits him as an intern at Oscorp, dangling a future partnership in front of him. Over the season, Peter fights a rotating cast of small-time criminals armed with high-tech gear supplied by a rogue Oscorp scientist, Otto Octavius. Around him, his classmates get pulled into their own trouble: Lonnie Lincoln is coerced into a gang and ends up with superhuman abilities of his own; Jeanne Foucault moonlights as the vigilante Finesse; and a masked vigilante investigating Oscorp's dealings turns out to be this world's own version of Daredevil.
In the finale, Octavius's secret "Project Monolith" turns out to be an attempt to open an interdimensional gateway. When it activates, a symbiotic alien creature comes through it. Doctor Strange reappears to close it down, and in the process accidentally sends himself and the creature back into Peter's own past — which turns out to be the actual explanation for how Peter's spider got there in the first place. Norman recovers a fragment of the symbiote that's left behind. Elsewhere, Harry Osborn quietly starts his own company, W.E.B. (Worldwide Engineering Brigade), to back young inventors without his father's strings attached.