It is a sequel to previous Connelly novel The Poet. Serial killer The Poet, whose death was suspected but not confirmed, turns out to be still alive and active. And what's more, the Poet has sent a message to FBI agent Rachel Walling, who tried but failed to catch him. Now the Poet is back and has ensnared Walling in a new game of cat-and-mouse.
Meanwhile, former LAPD detective Harry Bosch (Connelly's most frequent protagonist), now a PI, is investigating the death of his old friend and former FBI agent Terry McCaleb. McCaleb, a heart transplant recipient (and the protagonist of Connelly novels Blood Work and A Darkness More Than Night), died when his body rejected the donor heart. The authorities have written it off as natural causes, but his widow suspects foul play. Bosch starts to suspect foul play as well when his investigation reveals that McCaleb had a stalker—who turns out to be The Poet.
Tropes present in this work:
- Battle in the Rain: Climaxes when Harry Bosch fights The Poet in a pouring rainstorm.
- But for Me, It Was Tuesday: When Harry accuses The Poet of killing his friend, The Poet doesn't know who the friend is because he's "been kind of busy". Subverted because The Poet didn't kill Terry McCaleb.
- Catchphrase: Lampshaded when Kiz Rider quotes "Everybody counts or nobody counts" back at Harry. Followed very shortly by Harry considering his mission.
- Conspiracy Theorist: Bosch pretends to be one to encourage a reporter to dismiss his claim that McCaleb was murdered rather than start digging into it.
- Continuity Nod:
- Buddy complains about his representation in the movie, and after confirming that he got paid for his story, Harry tells him to "put your money in the bank and forget about the rest." This is not idle advice, but the voice of experience. Long ago, Harry got a big payday after having one of his cases made into a movie: it's how he can afford his house in Hollywood Hills.
- While visiting his ex-wife and daughter in Las Vegas, Harry lives in a short-term apartment next to a woman who is strongly implied to be Cassie Black, heroine of previous Connelly novel Void Moon. Later Connelly novel The Closers confirms that this is in fact the case.
- Bosch mentions taking saxophone lessons from an old jazz man that he met during a case. That's the plot of short story "Christmas Even" and an element of previous book Lost Light.
- It's established in Blood Work that McCaleb was part of the Poet investigation. In this book the Poet is revealed to have been stalking him.
- Down L.A. Drain: The setting for the climax. The Poet is swept away and drowned in a flooded LA storm drain.
- Enhance Button: Averted. Bosch, who for all his skill as an investigator is not handy with computers or electronics, asks for a digital photo to be enhanced and is told that it's impossible.
- Everyone Owns a Mac: "I looked down at the desk and saw the white laptop with the recognizable symbol of an apple with a bite out of it in silouhette."
- Glad-to-Be-Alive Sex: Harry and Rachel do some mattress dancing the day after they are nearly blown up by Backus's booby trap bomb.“We fell onto the bed and made survivors’ love. It was quick and maybe to some degree even brutal—on both our parts. But most of all it satisfied the primal urge in both of us to fight death with life.”
- He's Back!: Villainous version in-universe: the call Rachel gets at the beginning of the book.
- Incredibly Lame Pun: Not wanting to tell his ex-wife why he no longer plays the saxophone, Bosch says his teacher wanted him to "switch from alto to tenor - as in ten or fifteen miles away from him". The joke is, by Bosch's own admission, lame.
- Insistent Terminology: While in Vegas, Harry met a card counter who prefers to be called an "advantage player".
- Medication Tampering: As an elaborate form of suicide. Terry McCaleb tampered with his own heart medication instead of submitting to a second heart transplant.
- Narrator: Harry's part of the narrative is told by Harry in first person singular. Of the dozens of Bosch novels that Connelly has written, this and Lost Light are the only two which use Harry as a narrator.
- O.O.C. Is Serious Business: A subtle hint to the Twist Ending. Harry realizes that Medication Tampering isn't the Poet's style.
- Posthumous Character: Terry McCaleb, where one of the mysteries is how he died. Bosch uses McCaleb's notes for his investigation, and calls Terry his "silent partner".
- Reassigned to Antarctica: The book starts with Rachel Walling having been assigned to the Pine Ridge Indian Reservation as punishment for having an affair with a reporter in The Poet.
- Red Light District: Clear, Nevada, is a Pitiful/Hostile version. The fact that many of the men who go there take measures to conceal their journey make it the perfect hunting ground for the Poet, at least until his body count gets high enough for the Las Vegas Metro Police to start making connections between the men who have vanished without a trace over the course of a couple of years, and Terry McCaleb to figure out the common denominator. The Poet also previously operated in the RLD in Amsterdam for the same reasons.
- Sequel: To The Poet and somewhat to A Darkness More Than Night. While all of Connelly's books are in the same universe, this is his only sequel to a prior novel, the only one where a villain returns.
- Serial Killer: The Poet is up to his old tricks, although this time, he's doing it in part to settle an old score with Rachel Walling.
- Shout-Out: To The Film of the Book of Blood Work. Clint Eastwood is said to have attended Terry McCaleb's funeral. Terry's old friend Buddy appears in this novel and complains about how he was portrayed in the Blood Work movie.
- "Shut Up!" Gunshot: Rachel does this when two whorehouse bouncers are about to mangle Harry Bosch.
- Suicide, Not Accident: Terry McCaleb's death was written off as a heart attack, but Bosch suspects that the Poet killed him. Instead, Bosch eventually figures out that McCaleb was facing another heart transplant surgery due to his body rejecting the donor heart. But another surgery would have bankrupted his family, so McCaleb tampered with his own pills, which brought about heart failure and death.
- Switching P.O.V.: Switches back and forth between Bosch narrating his own story in first person, and a third person narrative following Rachel Walling and the Poet.
- Title Drop: The storm drains that Bosch and the Poet wind up falling into are called "the Narrows".
- A True Story in My Universe: In this novel, The Poet is a true-crime story and Blood Work is a true-crime film.
- Twist Ending: One you'll get a heads-up to if you pay attention to Backus' dialogue: He didn't kill Terry.
- You Have Outlived Your Usefulness: The backstory reveals that after Bob Backus got a Back-Alley Doctor to perform plastic surgery on his face, he murdered the doctor and his wife.
