After Nick is found to have been killed with all the evidence pointing to Natalia as the killer the rest of the team has been sidelined by the Internal Affairs investigation. Horatio with the help of the night shift lab and Calleigh’s ex-boyfriend have to find the evidence to clear Natalia.

The CSIs investigate when the parents of a baby sitter in an upscale neighborhood are murdered. As the team sorts through the neighbors' secrets and lies, they find an unexpected love triangle as a motive for murder. Meanwhile, a key piece of evidence found at the crime scene leads Horatio to expose a doctor with some dirty secrets of his own.

After a scalped body is found near a Native American casino, Horatio believes that the owners of the Casino and the County Supervisor may have had some involvement in the murder.