Duane (Dog) Chapman guest stars as himself. While Dog's apprehending a suspect, he encounters a murder victim. The investigation into the murder requires Catherine to go undercover at the local roller derby to find the guilty party. CBS/Global, 8 p.m.
Eric Casaburi, CEO of Retro Fitness, works undercover at one of the gyms in the hopes of improving the business. His experience produces one of the most dramatic reveals in the show's history when he confronts a rude employee. CBS, 7 p.m.
Three brothers from Boise come to the Sharks hoping they will want to invest in their unique product. Their family business revolves around eyewear that's made from sustainable wood, and the tycoons must decide whether it's worth the investment. ABC/CTV, 7 p.m.
George Stroumboulopoulos: Steve-O
Jay Leno: Wanda Sykes, India.Arie
David Letterman: Jim Parsons, Snoop Lion
Jimmy Kimmel: Anna Paquin, Brad Keselowski
Craig Ferguson: Tenacious D, Cathy Ladman
Jimmy Fallon: Paul Walker, Joss Whedon