An average suburban mom, Mrs. Olsen, calls her son, Henry, to breakfast. She hears no response, then finds the boy floating in the blood. Blood is in the water and pooled on the sidewalk near the body. The case comes into the VCU and Agent Ryan and Rebecca head out to the scene. While Agent Ryan and Rebecca look around the house, they hear a disturbance outside. A group of neighbors is shoving Theodore Bunch, the development's groundskeeper, toward the police, declaring him to be the murderer.
As Bunch sobers up in an interrogation room, the witness that fingered Bunch is brought into the station. A young girl from the neighborhood, Madison St. Clair, is interviewed by Agent Ryan as Rebecca watches on camera from another room. Madison claims that she saw a crying Henry running out of Teddy Bunch's place. Madison cries that she saw this from her tree house, but she didn't say anything because she's not supposed to be up there after dark. Madison wails for her mother and Agent Ryan leaves the room. But on the camera, Rebecca notices Madison happily swinging her legs and humming. When her parents enter the room, she turns on the waterworks again.
Rebecca thinks Madison is the killer. Her colleagues think it's Bunch. Virgil tells Rebecca she's now competing against them to prove who killed Henry. Rebecca visits Mrs. Olsen at home, who explains that Henry was an odd boy who was picked on a lot. She was happy that Henry found solace with Teddy Bunch, but now blames herself for letting Teddy close to her son. Rebecca asks if Henry started coming home with bruises after transferring to the school Madison St. Clair attended. Meanwhile, Agents Love and Ryan are searching Bunch's shack. They find a box of pictures of young boys, included Bunch himself as a child.
The next day, Rebecca drops by Madison's tree house. She hears Madison yelling at Nora, another girl from the neighborhood. Madison says she saw Nora talking to Rebecca the day before and she had better keep her mouth shut. Nora exits, leaving Madison and Rebecca alone. Rebecca begins to threaten Madison, telling her she knows what she did, but then Madison yells "Please don't hurt me!" and jumps out of the treehouse. Mrs. St. Clair comes running to find her daughter holding her arm in agony.
Back at VCU, Virgil tells Rebecca to avoid Madison, but doesn't remove her from the case. Rebecca begs Agent Sim to get up into Madison's treehouse and take some photos that will prove that Teddy Bunch's shack can't be seen from the treehouse. Meanwhile, Agent Ryan is focusing on Teddy's collection of fishing knives. He fought bitterly with his mother to get the knives after his father's death. Rebecca calls Agent Sim to ask if she can find a box of knives in Madison's treehouse. She does, but two knives are missing.
At school, Madison tries to get Nora to walk home with her. But before she can, Mrs. Olsen shows up and grabs Madison. She slaps her and Madison drops a knife. Mrs. Olsen runs off with Madison. Agent Ryan and Rebecca get word of what's happening. At the same time, Mrs. Olsen has Madison in her car, demanding to know what she did to Henry. Later, Mrs. Olsen drags Madison to the pool behind her house. A bawling Madison cries that she did it. Mrs. Olsen picks up the knife and moves in.
Agent Ryan and Rebecca finally arrive on the scene, only to find Mrs. St. Clair and Madison covered in blood, a shovel nearby and Mrs. Olsen floating in the pool. Mrs. St. Clair tells the detectives that Mrs. Olsen was about to hurt Madison.