This is Joe Ide's fifth novel in his IQ series, featuring intrepid detective Isaiah Quintabe. It made the WSJ's list of the best mysteries of 2021, one of my reading projects. (Which required that I first read IQs 1-4.)
I said "detective" above, but IQ really wants to get out of that business. His past exploits have given him PTSD; worse, many bad people in LA want to kill him. So he takes off to the north, landing in the picturesque town of Coronado Springs, But trouble finds him in the form of Billy, who's busted out of an asylum on a crusade: to save the lovely Ava, his high school crush, from a serial killer.
(One of those odd coincidences: while reading this, I was concurrently reading Lethal White by Robert Galbraith. It's plot also involves its protagonist getting roped into a mystery by the ravings of an unbalanced person also named Billy. At my age, such things can be confusing.)
Meanwhile, back in LA, IQ's retinue try to solve their own problems without his help. Ex-thief, ex-drug dealer Dodson is trying to go legit working as an unpaid intern for an ad agency; he's assigned to a glum has-been who's simply trying to hang on despite his burnout years ago. Deronda, the food truck mogul, is being extorted by a guy with whom she had a one-night stand years back, resulting in a child; IQ's estranged girlfriend Grace helps her out. And a hired killer from a previous series entry is very interested in tracking down IQ, and he sees Grace as a way to do that.
It's certainly a page turner, especially near the end, with a climax full of violence and physical damage to everyone involved. It's also funny in a number of spots, especially when a reluctant tutor tries to shed Dodson of his inner-city ways.
If I had a gripe, it's that Dodson's ad agency odyssey is a little too neat and tidy.