Published in 2026, Ironwood is a crime thriller by Michael Connelly, an acclaimed author known for his realistic police procedurals. Connelly, a former crime reporter for the Los Angeles Times, has penned several best-selling series, including those featuring Los Angeles Police Department (LAPD) detective Harry Bosch, beginning with The Black Echo, and defense attorney Mickey Haller, beginning with The Lincoln Lawyer, which have been adapted into popular television shows. Ironwood follows the protagonist introduced in the first novel of the Catalina series, Nightshade: Detective Sergeant Stilwell, the reluctant supervisor of the Catalina Island sheriff’s substation, a posting for deputies who have fallen from grace. When the murder of one of his own deputies during a botched drug sting exposes a cover-up within his department, Stilwell is forced to conduct a rogue investigation. At the same time, a chance discovery plunges him into a cold case involving a serial killer who preys on solo hikers, connecting his work to that of recurring Connelly character LAPD Detective Renée Ballard.

The novel weaves its two parallel investigations on both Catalina Island and the coast of California, grounding its plot in real-world contexts such as the unique ecology of Catalina, the notorious tactics of the LAPD’s Special Investigation Section, and esoteric military traditions like the Marine Corps “Hog’s Tooth.” Through these layered narratives, Connelly explores several key themes. The island’s remote beauty creates a deceptive sense of safety, illustrating how Isolation Amplifies Vulnerability for both residents and law enforcement. The hunt for the serial killer becomes a study in criminal psychology, examining The Self-Destructive Nature of Criminal Arrogance. Most centrally, Stilwell’s pursuit of his colleague’s murderer forces him into a direct confrontation with a compromised command structure, providing a stark look at how Institutional Protection Enables Violence by shielding corrupt officers to preserve the department’s public image.

This guide refers to the 2026 Little, Brown and Company first edition.

Content Warning: The source material and guide feature depictions of graphic violence, illness, death, death by suicide, physical abuse, emotional abuse, and cursing.

Plot Summary

Detective Sergeant Stilwell, the supervisor of the Catalina Island sheriff’s substation, orchestrates a nighttime surveillance operation at the island’s airstrip. The mission is based on a tip from Deputy Alton Quigley’s confidential informant about an incoming drug plane. As the plane lands and drops a duffel bag, a man on an ATV enters the airstrip. Stilwell orders his team to move in, but the ATV flees. Stilwell gives chase down the treacherous mountainside, leaving Quigley and Deputy Ilsa Ramirez to intercept the plane. When Stilwell loses the ATV, he returns to the airstrip to find Quigley dead from a gunshot wound to the head and Ramirez critically wounded with a neck injury. The plane and its pilot have escaped. Stilwell’s superior, Captain Corum, arrives from the mainland and removes Stilwell from the investigation. Despite the order, Stilwell tracks down and arrests the man on the ATV, Kalas, the next morning. However, Kalas is soon taken from the substation jail by two men posing as US Immigration and Customs Enforcement agents, an event that Stilwell suspects was an inside job.

While sidelined and tasked with cleaning the substation, Stilwell discovers a high-end backpack in the lost-and-found that was turned in two months prior. Inside, he finds a set of keys, including a high-security Medeco key that he traces to Angela Metier, a woman who vanished four years earlier while hiking on the island. He contacts the LAPD’s Open-Unsolved Unit and connects with Detective Renée Ballard, who confirms that Metier is one of several missing female hikers believed to be victims of a serial killer. Stilwell and Ballard find Metier’s skeletal remains in an ironwood grove. Inspired by the investigative methods of Ballard’s mentor, Harry Bosch, Stilwell reviews old news footage from the search for another victim, Candace Neary. He spots a man being interviewed near the distinctive tree where Neary’s body was later found and recognizes him as Kent Middleton, a park ranger who now works on Catalina.

As the serial-killer investigation unfolds, Stilwell learns from the recovering Ramirez that she and the married Quigley were secretly having an affair. She reveals through writing on a tablet that just before the shots, the sniper yelled Quigley’s name, confirming that the ambush was a targeted assassination. Ramirez also reveals that Quigley’s wife was having an affair, which Quigley’s defense attorney confirms, hinting that Quigley’s wife was sleeping with his boss, Lieutenant Gavin Lambert. This new information, combined with Kalas’s suspicious release, convinces Stilwell that there’s a departmental cover-up. The official investigators on the case, Ernie Simon and Bob Trestle, are abruptly removed under the pretense of retirement and vacation. All inquiries are redirected to Corum, heightening Stilwell’s suspicions. Meanwhile, Ballard’s team confirms that Middleton is their prime suspect. They discover that he’s actively cyberstalking a new potential victim, a hiking guide named Molly Young, and has booked a private hike with her in Angeles National Forest under a false name.

The LAPD’s elite Special Investigation Section (SIS) mounts a large-scale surveillance operation to intercept Middleton during the hike. At the trailhead, Middleton’s plan to isolate Young is thwarted by the SIS team’s presence. Having already disposed of his murder kit, Middleton is arrested at the trailhead with no physical evidence. Ballard and Stilwell agree to hold Middleton for 48 hours.

Facing the prospect of releasing a known serial killer, Stilwell theorizes that Middleton, too clever to be caught with evidence, must have stashed his murder kit somewhere after realizing that he was being followed. He deduces that the only unobserved place was the Reagan State Building, where Middleton had a job interview after getting off the ferry. A search of the building proves fruitless until Stilwell suggests checking inside the ceiling of the elevator that Middleton rode alone. There, they find Middleton’s backpack containing a detailed murder journal, a garrote, a folding shovel, and other items. In an interview room, Ballard and Stilwell confront Middleton with the evidence, and he’s officially arrested. The following morning, however, Ballard informs Stilwell that Middleton died by suicide in his jail cell.

With the serial-killer case closed, Stilwell returns his focus to the airstrip murder. He uncovers Lambert’s military record, revealing that he was a decorated Marine Corps scout sniper. A metallurgic report on a bullet fragment from Quigley’s skull identifies a rare, frangible round manufactured by MIPCO Ammo, a company owned by Walter Bessemer, a former Marine who served with Lambert in Fallujah, Iraq. Posing as Lambert, Stilwell calls MIPCO and speaks to Bessemer, but the call tips off Lambert. Stilwell confirms through marina security footage that Lambert and Bessemer used Bessemer’s boat, the Bullet, to travel to Catalina on the night of the murder.

Knowing that Lambert and Bessemer are now en route back to the island to silence him, Stilwell sets a trap at the substation. He knows that Corum is monitoring the station’s security cameras. He lures Lambert into his office by playing a recording of an old interview. As Lambert prepares to breach the door, Stilwell ambushes him, disarms him, and locks him in a holding cell. Corum calls, revealing his complicity, and attempts to blackmail Stilwell, threatening to blame him for Kalas’s escape unless he releases Lambert. Stilwell refuses, powers down the substation’s entire audio/visual system to cut Corum’s feed, and places a call to Lionel McKey, a reporter for the Catalina Call, preparing to expose the entire conspiracy.