When a student is arrested and tried for the murder of a popular high-school girl, the suspect's 12-year-old sister confesses to the crime. This results in the judge giving the prosecution 72 hours to re-examine the evidence before the jury delivers its verdict.

Sara questions her future as a CSI when a past case comes back to haunt her, the 12 year old Hannah, who has to back up her brother one more time with all new tricks up her sleeves.