Greg Fitzsimmons does some stand-up comedy. This guy is funny, but then he makes an abortion joke. Wow, this is an uncomfortable start to a CSI episode. Some dude starts heckling because he doesn't find abortion funny. After the show, it seems that the comic is the one who's going to die, but it is only a lead-in to the real crime. The comic gets in his car to drive away and sees a small box. It contains a dead child. Cut to the Opening Credits.
The CSI team gets to work performing an autopsy. Grissom (William Petersen) finds some hairs in the packing tape of the box. Catherine Willows (Marg Helgenberger) seems a bit more torn up by Baby Cordelia than most victims. She's offended by Hodges' claim that the death of a pretty little girl is more tragic than the death of a plain or ugly child.
Nick (George Eads) and Warrick (Gary Dourdan) head to the crime scene to plant a camera inside the memorial to the little girl.
Hodges finds dark roots on the girl's hair, and fellow analyst Wendy determines the dye job was done two to three days ago. Grissom then does some technical stuff which leads him to the owner of the box, a flighty woman who bought a vacuum cleaner. She introduces Captain Brass (Paul Guilfoyle) and Willows to her fiancé, Dean James, who claims they just threw the box out. Wendy runs the hairs from the box through the database and the search reveals that Dean James (aka Leo Finley) has a criminal record.
Leo explains he did some E and danced around naked, though it just happened to be near a pre-school, so he's now a convicted sex offender. Brass and Willows have no sympathy. Grissom, on the other hand, wonders why he's in custody, because he's more reasonable and less emotional than Willows. Nick follows a lead to a mechanic near the scene of the crime, who informs him that Leo brought an engine in for fixing in the vacuum box. Leo tries to explain himself again, making Brass even more suspicious.
Warrick does some computer work going through missing persons reports, settling on a Lebanese girl. They bring in the parents, but she's not their kid. In a prison, an inmate sees a news report of the murder and goes nuts when he recognizes the dead girl as his daughter. The inmate suspects his ex-cellmate Boyd, who checked in on the inmate's wife, then married her.
Grissom and Willows head to Boyd's house, which they determine is the murder scene thanks to some blood on the sink pipes. They find Boyd in a diner, but he takes hostages and holes himself up inside. Boyd releases the kids, then is eventually talked into letting everyone else out. These are not the actions of a man who murdered his step-daughter. Guns are fired, and Boyd's wife gets caught in the crossfire.
In custody, Boyd is all-too-willing to take the fall for the little girl's death. Outside, Willows tries to calm down Boyd's biological children, who tell her they were playing hide-and-seek and told Inez to hide under the sink. Willows then tries to convince Boyd to tell the truth, that it was an accident because Inez died because she was locked in the cabinet under the sink. He didn't report it because he didn't think anyone would believe him and he'd go back to jail.
Case closed, Willows heads to her car and is stopped by Leo. His flighty girlfriend left him and told his boss that he was a registered sex offender. Now he has no relationship, job or place to live, and he's taking his anger out on Willows. She gets worried and draws her gun. He claims that, if he decides to kill himself, he'll go to her house and do it in front of her because she ruined his life.