Two teens out driving hit a man. The team agreed to de-clutter but some do it better than others. Ducky is filling in for Palmer.The teens didn't kill Petty Officer Noah O'Donnell with their car, as Ducky discovers three bullet holes in the body. He was executed. A local detective, John Fischer, is looking into Noah's death and told Noah's boss to keep it quiet. He also investigated Noah's parents' murder. Noah's parents were killed exactly the same way. Noah's sister Claire is missing. Palmer didn't find any bullets in the body, just like with the parents. Noah's body was found exactly where he had ran out after his parents' death. Noah's boss Porter Brandt says Claire has issue. A shed on the O'Donnell property houses crime-scene dollhouse recreations. Ducky says the dollhouses are "nutshell studies." He says Claire is trying to find her parents' killer. The news leaks out about Noah's murder. People start invading the O'Donnell crime scene, and they want to lynch Claire. But she's at the site where Noah died, talking to him. Gibbs brings her in. Claire said Noah discovered something about his parents' murder that someone didn't want him to find. Claire blamed herself for that. Fischer comes in demanding to speak to Gibbs. He's been looking out for the O'Donnell kids. Jack tries to analyze Claire. Noah had built a model of a different cold case. Gibbs takes the team through the details of the crime scene. Brandt killed Noah after Noah determined Brandt had killed Louise Fitzgerald in what was ruled an electrical fire after he robbed her. Jack gives Claire the name of a therapist. Ducky makes a call and gets Fischer permission to exhume the body of the last suspect in the O'Donnell parents' murder. Odette texts Bishop.