A mangled body is found mashed into a road near a campsite. The head is missing, and the team determines the victim was dragged along the road by an 18-wheeler. Papers stuffed into her bra turn out to be shopping coupons. Special Agent Genny Shaw helps identify the vehicle, and Booth and Brennan find the victim's head on the vehicle's underside, but the shocked driver pleads innocence. The duo realize that the victim was hiding under the truck from someone, someone who attacked her, and got trapped in the driveshaft when it pulled away. But who was she hiding from? The victim's husband says she was an "extreme couponer," obsessed with saving money. When fragments of her skull are found in the parking lot of the supermarket where she made her final purchase, Booth and Brennan may be close to finding the person who attacked her. But is it the aging checkout lady who hated the couponers, or one of the victim's overcompetitive couponer friends? Agent Shaw discovers evidence that may lead to the true culprit, but some misidentified blood turns out to hold the final clue.
Meanwhile, Brennan deals with her first day back at work after giving birth. She intends to parent rationally, but her emotions get the better of her as she tries to adjust to being away from the baby for the first time. And Cam regrets advising overly-studious intern Finn to have some fun and date a little when he begins dating Cam's daughter.