Katie is a high school senior in Somerville, MA. She babysits her neighbors' younger son, Toby, while having a crush on their older son, Dean, who she was best friends with as a child, before they grew apart. Katie is nerdy and does marching band. Dean is popular and plays basketball. Katie never misses an opportunity to babysit and be in Dean's house, daydreaming about him.

One day, during marching band practice, a plan crashes near the school. While Katie didn't actually see the plane--she was at the water fountain--she pretends she did, because it makes her life feel eventful and special to do so. For a brief time, the crash draws attention (reporters, etc.) to their small city, but that soon subsides.

Toby tells Katie he and his friends have been searching for treasure (cheap earrings, etc, that they believe are valuable) from the plane crash in the woods behind the Burger King. He shows Katie a cheap earring he found. Katie says some girl probably lost it, and Tony asks why a girl would be in the woods behind the Burger King. Katie thinks he'll find out in time.

One day, Dean asks Katie, who continues to lie, what seeing the plane was like and confesses he wishes he saw it. He says his little piece of the plane is in her.

On Halloween, Katie is babysitting and Toby and his friends, after coming home, disappear from the house. Katie wakes up from a nap and finds them gone. Then Dean gets home from a Halloween party. He's drunk. Katie tells him what happened and drives with him to Burger King and they go into the woods.

Dean, drunk, suddenly asks Katie why they stopped being friends. Then he grabs her wrist and kisses her. She falls and he's on top of her. It's really unpleasant for her--the weight of him, the drunken manner in which he kisses her--and she tells him to stop. He hears Toby and the other boys. He gets up, then turns back and helps her up. He apologizes for kissing her--Katie doesn't know if he's apologizing for kissing her in that way or for kissing her at all.

They find the boys naked in a murky pond, looking for treasure. Toby is excited because they found a bobby pin. Dean tells Katie: "That's just like something we woulda done [as kids]. I love it. It's totally crazy." He takes off his clothes to join them. The narrator wonders what they hope to find and imagines it's a memento to give back to the town as proof of their existence.