In “Desperado,” his last novel, Manuel Ramos introduced Gus Corral, a North Denver Hispanic man with good intentions and bad instincts. Now Ramos brings back an older, more mature Gus in “My Bad,” and teams him up with Luis Montez, a lawyer from Ramos’ early books. It’s a brilliant combination, and as a result, “My Bad” is arguably Ramos’ finest novel. Corral has just been released from prison for unspecified crimes and is determined to turn around his life, despite a hard-nosed parole officer who’s betting against him.