According to the Mafia Script

In the trunk of a Rolls-Royce, with two bullets in the back of his head, Tony Aliso is found, the owner of a Hollywood studio and an avid gambler. Apparently, he became a victim of a mafia hit. To investigate... the theory of murder over gambling debts or fraud, Los Angeles police detective Harry Bosch heads to Las Vegas. During the investigation, it turns out that shortly before the filmmaker's death, he was seen at a poker table with a certain Eleanor Wish – a former FBI agent, a former convict... and the former love of Harry's life. Suddenly, this case becomes very personal for Bosch, and now he has to 'keep his cards close to his chest.' Meanwhile, he is gaining enemies, and they are not only thugs from Vegas, but also someone from the internal affairs division of the police. But when has danger ever stopped Bosch?