Full story
After the Battle of New York, Adrian Toomes runs a small salvage crew hauling away the wreckage of the Chitauri invasion. He loses the job when the Department of Damage Control, tied to Tony Stark, takes over. Furious, Toomes keeps some of the alien tech and starts an underground weapons business with his crew. For himself, he builds a winged suit. The Vulture is born.
Years later, Peter Parker comes back from the fight in Germany thrilled, but Tony tells him he isn't ready to be an Avenger. Peter skips his school's academic decathlon team to patrol Queens as Spider-Man while waiting for a call that never comes. His best friend, Ned, finds out his secret. When Peter breaks up a weapons deal, the Vulture drops him into a lake. Tony saves him with a remote-controlled suit and tells the kid to stay out of it.
Peter doesn't listen. With Ned, he disables the suit's tracker and unlocks all its hidden features. He follows the weapons trail to Washington, D.C., where the decathlon team is competing, and ends up rescuing his classmates, including his crush, Liz, from an elevator in the Washington Monument after a Chitauri power core blows up. Back in New York, he tries to catch a buyer on the Staten Island Ferry, but a faulty weapon splits the boat in half. Tony has to clean up the mess and takes the suit away.
Peter asks Liz to the homecoming dance. When he picks her up, he learns her father is Toomes, and Toomes, during the car ride, figures out who Peter is. He threatens Peter and lets slip his plan: hijack a Stark plane moving gear from Avengers Tower to the new compound. Peter leaves the dance, puts on his homemade hoodie suit and, with Ned helping from a computer, takes down Herman Schultz, the Shocker. Toomes drops a building on him. Peter lifts himself out of the rubble, catches the plane and crashes it on the beach at Coney Island. When the Vulture suit explodes, Peter saves Toomes's life, and Toomes goes to jail.
In the end, Liz moves away, and Peter turns down Tony's offer to join the Avengers full time. He'd rather look after his neighborhood. Tony gives the suit back. At home, Peter puts it on just as Aunt May walks in and sees everything. In the mid-credits scene, Mac Gargan asks Toomes in prison who Spider-Man really is. Toomes keeps the secret. What Gargan plans to do next is left open.