It's a bad night at fast food restaurant Choozy's Chicken: the signature chicken statue crashes through the restaurant's window and Bob Graham, the head manager is found dead in the kitchen. Langston and Nick examine the area, discovering that someone has been living in the kitchen of the fast food joint. The two find a blood pattern that indicates a body was dragged outside, suggesting that there's a second victim. They follow the blood to the dumpsters and grease containers, but Langston notes that the container for Choozy's chicken is missing--and has been replaced by one for a Chinese restaurant. They also discover skid marks and a side mirror broken off from a vehicle. Riley looks in the drop safe in Bob's office to see if the restaurant was robbed while Brass talks to Kiwi Long, the usual night manager, who says Bob was covering her shift. She mentions an employee named Elizabeth Martin was closing up the night before, but that she hasn't been able to reach her. Nick finds blood on a 'wet floor' sign in the restaurant while Dr. Robbins conducts the autopsy, determining that a strong blow to the head that severed Bob's spinal cord was the cause of death. Nick and Langston get a lead with the side mirror, leading them to a frat boy named Max Stanton, who has a prior for assault against Bob. A former Choozy's Chicken employee, it quickly becomes evident to the two CSIs that the only thing Max is guilty of is theft: he was attempting to make off with the Choozy Chicken in his truck but failed. The team prints all of the Choozy's Chicken employees, but two are missing: Elizabeth Martin and Gary Comstock. Brass finds evidence that 'Elizabeth Martin' is an assumed name, while Wendy finds Gary, a former drug addict, is in the system--and that his epithelials were in a razor found at the restaurant, indicating he was the one living in the kitchen. Mandy runs the fingerprints found next to the broiler but doesn't get a match to Bob or any of the employees. She matches prints on Elizabeth Martin's closing receipt to prints on the 'wet floor' sign, but without Elizabeth's prints for a comparison, she can't say for sure that they are Elizabeth's. Riley finds menstrual blood in Bob's office, but no sign a sexual assault or struggle took place.
The team turns to surveillance footage from the nearby Chinese restaurant's camera and sees several people getting out of a van and stealing a grease container. The plates are registered to one Timothy Rand. Langston and Brass go to Rand's house in the desert and find him distilling grease into biodiesel fuel. Langston opens up the container from Choozy's and finds a male body inside. The man is identified as Gary Comstock, and Dr. Robbins determines the man was asphyxiated in hot chicken grease. Hodges finds the remnants of glasses and nine 20-dollar bills in the grease Gary was dumped in. Langston, Riley and Nick return to the scene and posit that Bob killed Gary and dumped his body, but are baffled by the print next to the broiler, which didn't match Bob. Nick asks Mandy to run the print again and she does, noticing this time around that it's inverted due to pressure. Once that is factored in, the print proves to be a match for Bob. Brass calls Nick: INS has found Elizabeth Martin and determined she's an illegal immigrant. Brass questions Elizabeth, whose real name is Rosa Gonzales, and she tells him she was indeed closing the night Bob was killed. Bob claimed her receipts didn't add up and forced her to undress so he could do a strip search. Gary walked in and caught him feeling Rosa up and confronted Bob. Bob went after Gary and Rosa dressed and ran out to find Bob winning the fight. She picked up the 'wet floor' sign and struck Bob in the head. Gary told her to run and she did. Brass tells her the blow from the 'wet floor' sign wasn't what killed Gary. Langston, Nick and Riley ponder the question and Langston posits that without his glasses (which fell in the chicken grease) and suffering from a blow to the head, Bob's balance may have been off--he likely slipped in the chicken grease and tumbled backwards--hitting his head on the floor hard enough to sever his spinal cord.
Catherine and Greg investigate the death of Melinda Tucker, who was killed handcuffed to her bed while her husband Scott, a real estate agent, was passed out drunk on the couch. Catherine takes the wine in Scott's glass back for processing, while Greg notices two tubes of toothpaste in the trashcan. Dr. Robbins shows Catherine and Langston, who stops by to observe, that Melinda's stomach was filled with toothpaste. Hodges confirms her death was due to fluoride poisoning and points out that she was fed twice the amount needed to kill a person her size. Greg and Vartann question Scott, who had the key to the handcuffs in his pocket. He's fallen on hard time and his wife had a large life insurance policy--did he decide to get rid of his wife? Scott claims that he and Melinda hadn't had sex in months, and also notes that Melinda was a dental hygienist before they married--she would have kicked him where it counted before letting him feed her a fatal amount of toothpaste. Greg starts squeezing out the toothpaste from the Tuckers' home, but stops when Hodges tells him and Catherine that the toothpaste that killed Melinda had a bleaching agent in it, which the toothpaste the Tuckers had did not. Catherine and Greg return to the Tucker house but don't find any toothpaste with whitening on the premises. Greg notices a shoe mark on the fence and thinks to check the eighty-year-old neighbor's trash--and comes up with two tubes of whitening toothpaste and a pair of used latex gloves. Back at the lab, Greg makes a startling discovery--the DNA in the gloves is Melinda's. She fed herself a fatal dose of toothpaste, spiked her husband's wine and then handcuffed herself to the bed to frame him for murder. Scott tells Catherine that his wife was deeply unhappy when his clients started to lose their houses and blamed the Tuckers. The clients she'd socialized with and became friends with blamed her--and she blamed Scott. Dr. Robbins approaches Ray--he's found an space in the morgue he can use for an office. It's not much, but Ray is quite pleased with the accommodations.