In Peacock ’s mystery All Her Fault , Marissa Irvine (Sarah Snook) searches for her missing son. Composer Jeff Beal , who conducted some of the series’ music live at Deadline’s Sound & Screen Television, said the thriller score was the easy part. He also wanted to convey the characters with honesty. “It’s kind of about a lot of people who are human beings making very difficult choices and often the wrong choice, a moral choice,” Beal said. Jake Lacey plays Marissa’s husband, Peter. Peter’s not always the most supportive partner, but Beal gave him the benefit of the doubt — musically at least. “Even Peter the husband, there’s some sort of weird logic that follows everything they do,” Beal said. “Peter was obviously a narcissist but he had his own justifications. So I try to write from honesty.” Watch on Deadline Marissa anchors the show but may be an unreliable narrator. Beal doesn’t want to trick the audience, but he can reflect what drives her.…