Bosch meets detective Poydras and his new partner, Musso. Bosch chuckles at the name and asks what happened to the previous partner Franks. Musso and Frank Grill is a real restaurant in Hollywood and a shooting location for several episodes of Bosch (2014). It's often referred to as "Musso and Frank's".
The poster for the fictional TV mini-series, "The Black Echo", is now seen hanging on Bosch's office wall.