As a real estate agent shows a couple a house, they notice a smell. When they get to the bedroom, they find a pile of ashes next to a foot.

Booth tells Sweets and Bones that his grandfather is going stay with him for a while. He explains he left his nursing home after he punched a staff member. Booth says his grandfather just wanted to smoke a cigar in his room. His grandfather Hank comes in and calls Booth shrimp. Hank meets Sweets and figures he looks too young to be a doctor. Booth gets a call and learns about a case. Hank tries to volunteer, but Booth tells him he can't come along. Sweets volunteers to take Hank home.

At the scene, Bones asks Booth if he can handle taking care of his grandfather. The team meets with Katy, the real estate agent, and Howard the owner. Booth asks for a list of people who had access to the house. They see the ashy remains of the victim. They notice a birthday cake on one of the tables. Bones asks them to move carefully since the hand of the victim is about to crumble. After she receives a can of hairspray from the real estate agent, she uses it to keep the hand intact. Booth suspects that the man died from spontaneous combustion, but Bones has her doubts.

The team moves the mattress to the lab. Hodgins says Booth might be right about how the victim died. He says there are cases which shows fat could catch on fire. Clark and Bones figures the victim was set on fire postmortem since there are no signs of flailing. Cam reports the body showed no indications of drugs of alcohol. The staff is surprised after Clark says he feels moved by Booth's decision to take in his grandfather. He explains he was close to his own grandfather who he called Gramps. Clark believes that the victim was a female since the foot shows signs of Haglund's Deformity which is caused by wearing ill fitting shoes. They figure the victim was obese. Hodgins finds an orange goo on the mattress.

Booth learns that Hank was found by an officer at the park. While he says Hank was disoriented, Hank takes the phone and admits he was turned around. Booth tells him he will be there to pick him up. Katy arrives at the office and gives Booth a partial list of people who had access to the house.

Angela says she is making a three dimensional rendering of the hand. Hodgins reports that he found the orange goo came from a polyester material he suspects was a wig. Angela scans the material and finds it came from a polyester vest worn by employees from a retail store called PriceCo.