In “IQ,” Isaiah worships his older brother, Marcus, whom he regards as a role model and hero. But Marcus dies in a hit-and-run accident, and Isaiah has to raise himself, with the help of his wisecracking friend Dodson. “IQ” ends in a junkyard where Isaiah discovers the car that had hit Marcus, and “Righteous” starts in that same junkyard eight years later. The car is still there and still full of evidence.

Image Joe Ide Credit... Craig Takahashi

Isaiah sets out to discover how and why Marcus died — and Ide quickly turns the tables on his readers. What if Marcus wasn’t the hero his kid brother imagined? What if he led a dirtier life than Isaiah thought possible? In the prologue to “Righteous,” Isaiah discovers that the accident was no accident: Marcus was deliberately targeted. Whoever drove that car sat in it with a sandwich, waiting for Marcus to try to cross the street so he could make the kill.

As anyone who read “IQ” will know, Ide isn’t a one-plot type of writer. He sets many schemes in motion. In the new novel, they involve gambling, a natty Rwandan Hutu gangster who lost one leg to the Tutsi, Chinese triads, money-laundering, human trafficking and a whole lot more. Ide writes about the hostility among ethnic groups — notably black gangs and Chinese triads (whose members’ affectation of American gang habits comes in for some mockery, though their toughness does not) — in ways that would be offensive if they weren’t equal-opportunity insults. The world of these books is one of constant trash talk, and Ide delivers it with style.

None of it comes from Isaiah. He remains the one stand-up guy in the midst of hot- and cold-running human detritus. But eight years have changed him. He’s no longer the boy wonder we first met. He’s a grown man with no concrete future plans who solves neighborhood crimes mostly as favors — until he suddenly discovers motivation. (Dodson is now a family man, settled down with a woman who can talk back to him and a “Lil’ Tupac” expected any day.)

The galvanizing force is Sarita, Marcus’s girlfriend. When Isaiah crosses paths with her again, he starts imagining an adult life with wine, an actual sofa and the woman of his dreams.