This week’s episode starts with the adventures of three girls who are on their way to Las Vegas to party. Along the way they narrowly avoid an accident and drive off the road only to hit a pedestrian. The pedestrian survives and is taken to the hospital.
At the hospital Captain Brass tells Nick that the woman is Janet Marsh. He goes on to explain she was part of a case from three years earlier that involved her husband, daughter, and son disappearing and the husbands car being found abandon on the highway right where she was at when she was hit by the girls. Janet has effectively stopped living and has only been obsessing over her missing son for the last 3 years. However, she is really only obsessed with finding her son Adam, she admits she is less concerned with her husband or daughter.
While processing the items from the accident Wendy discovers that the flashlight that Janet was carrying had some dried blood under the lens. The blood turns out to belong to her son Adam. This reopens the case of her missing family members. This leads CSI to investigate Janet’s house which had not been searched previously.
While processing the house Nick intercept’s Janet’s brother Bill Marsh as he is was coming over to check on Janet (fresh out of the hospital from her accident). That for the last three years he had to make sure she ate, help her pay bills, etc. Nick explains that she out of the house right now and is ok but he would need to come back later. After he leaves as Ray joins Nick to help check the garage for traces of blood. Nick and Ray quickly find traces of blood having seeped from the ceiling above. Once they investigate in the crawl space they find a footlocker as the source. They open the footlocker and find desiccated remains.
The remains are identified through DNA as those of Adam Marsh, Janet’s son. Ray takes finger prints off the foot locker and links them to Mike Marsh (Janet’s missing husband) along with one unknown print. Greg hypothesizes that maybe the print is from Emily Marsh (Janet’s missing daughter) and attempts to use fingerprints from a handprint craft that Emily had made when she was younger. The fingerprints lifted from the crafts turn out to be a failure. Greg at the last minute decides to run the unknown print through AFIS and gets a hit to a work card for a girl in Reno, NV with a different name but same birthday as Emily Marsh.
Brass takes officers to Reno and finds the girl as she gets home and she has a son in the backseat. After DNA confirms that she is Emily, Nick and Ray find that the “husband” she has been living with under a different name turns out to be Mike Marsh. Mike shows up at the sheriff’s station and begs them to let Emily and her son go, that he had killed Adam and she had nothing to do with it. Janet overhearing this confession grabs a gun from an officer and shoots Mike. Greg finishes processing the DNA to confirm that Emily is the mother of the little boy and also finds that the child shares extra DNA from Janet’s side of the family.
Emily finally explains how Uncle Bill was coming to her even after he got her pregnant and Adam found out. In arguing with him to not say anything she hit him with the flashlight and called her dad telling him everything. Her dad says they can start over and was the one who put Adam in the footlocker. Finally Brass tells Janet that the DA is not going to press charges against Emily for Adam’s death and Janet is taken away to jail (for killing Mike). Uncle Bill is arrested for his actions against Emily, and Emily is reunited with her son, who she is filled with tears of joy to see.