Mary is a teenage girl sitting in the police department, when the book opens. Cops Sharp and Riles are grilling her on a boy named Richard “Rich”. Mary reveals that they went out once and hung out a few times, but he wasn’t her boyfriend, she was actually dating a guy named Charlie. The cops announce that Rich is lying dead on a slab in the morgue and Charlie is missing. They make it clear that they don’t believe she knows nothing about the night because she can’t remember simple details and all she say is that she loves Charlie and doesn’t know where he went.
Mary then flashes back on how she fell for Charlie. She had a shitty car and heard he was a good mechanic, so she took her car to him. He brought it back that night and wouldn’t take any money for it. She gave him a ride home, the car broke down again and she exploded on him, blaming him for wrecking her car. He called her a bitch, but brought her car back the next day in perfect condition, so she asked him out. Later she discovered that he spent the whole night working on the car, just for her.
The cops discover that he was shot with a .38, which is the same type of gun that Charlie’s dad owned. They call in Dick’s sister Hannah and she admits that her brother loved Mary, but denies that Charlie could have killed him. She does let it slip that the two guys had a bad fight over her at school. Apparently Rich/Dick promised Mary that his dad would help her get into Stanford, if she went to the school dance with him. She agreed, as long as no one told Charlie.
The cops bring in this chick Linda, who’s full of bad stories. She swears that Mary threatened to kill Charlie and she overheard it. She also swears that Mary and Dick were making out on the night of the dance and that multiple people thought they had sex. Mary denies it because Dick nearly raped her on their one and only date. The cops then take her to the crossroads, a local hangout, to help them look for Charlie and the murder weapon.
Mary flashes back to the night of the dance and remembers Dick attacking her again. She went to see Charlie, but he already knew that she lied to him and went out with someone else. He called her a whore, broke up with her and walked away. Then she went to Hannah and discussed the whole thing, making the comment about wanting to kill him.
In the present day, the cops take Hannah and Mary to the crossroads, where they find the gun and it matches the one belonging to Charlie’s dad. They talk it over and decide that since there’s no blood, it means that he was killed somewhere else and left there. They arrest both girls, drive down the road a little bit and find a huge ass pool of blood. There are also prints left in the snow and both match the shoes that the girls are wearing.
The cops also discover that both girls dipped their hands in Lysol, making it impossible to find gunpowder residue or any other evidence. They also discover that Dick was high on PCP. After letting them go, Mary remembers what actually happened that night. Dick and Hannah agreed to help her pull a prank on Charlie, to get him back. Yeah, because he was the one who did something bad! Mary made plans to meet him and then Dick would pop up, wave around a gun and threaten him.
As soon as she sees him though, Mary backs down. Just as they make up, Hannah comes running out of the woods. She tells them that Dick is in the woods and coming after Charlie with real bullets, instead of the blanks she gave him. Charlie rushed to her aide, the two guys fought, the gun went off and somehow they both ended up dead. Hannah forced Mary to help her dump Charlie’s body in an old abandoned well and make it look like he disappeared.
The two girls go out to a restaurant and talk about what happened. Then they see Charlie wandering down the street. It turns out that he was wearing a St. Christopher medal, which absorbed the shock of the bullet. Hannah wants to kill him and takes him out to an old abandoned farm. Mary agrees to do it, but then hits her with a brick and grabs the gun. She shoots her in the heart and takes Charlie back to her house.
Of course Hannah isn’t really dead and she shows up at her house. The two cops show up too and just as they’re trying to fool them, Charlie walks in the room and tells them Hannah shot him. Apparently she hid in the woods and used night vision goggles to get a good shot on him. She also drugged Dick, so he’d act crazy and uncontrollable. All of this because she had a lesbian crush on Mary!
After a minor confrontation with the cops, Hannah raises the gun to her head and plans to kill herself. Mary asks to give her one last kiss before she dies and they do kiss. Then she moves the gun down and Hannah bursts into tears. She promises to take the blame for everything that happened and talk to her dad about getting Mary into Stanford. I guess Mary and Charlie live together happily ever after?