Winters describes the work as an "existential detective novel", turning on the question of why people do things in spite of their long-term unimportance.

Each part has an introductory graphic giving the date, and the asteroid's right ascension, declination, elongation and delta, or distance from Earth, in astronomical units.

By August, not only is that likely, the probability of an impact reaches five percent, triggering an economic panic that results in the bankruptcy of prominent corporations including McDonald's, 7-Eleven, Dunkin' Donuts, and Starbucks.

As the asteroid, now popularly named Maia, approaches, its diameter is measured at 6.5 kilometers (4.0 mi), large enough to cause serious planetwide effects and the likely end of civilization should it strike the Earth.

The U.S. Congress passes the Impact Preparation Security and Stabilization Act (IPSSA), banning trade and production of firearms, imposing wage and price controls, and legalizing marijuana while toughening penalties for the possession or distribution of other drugs.

Social and economic order begins to collapse as people leave their jobs to do things they will never have a chance to again (known in the book as "Bucket Listers"), and many commit suicide.

In late March 2012, Henry Palace, a young detective with the Concord, New Hampshire police, is called to a crime scene: a man named Peter Zell has apparently hanged himself in the men's room of a former McDonald's.

The case seems clear-cut, but Palace wonders about the bruises on Zell's head and the fact that he was wearing a cheap suit but used an expensive belt to hang himself.

At Zell's apartment, Palace finds a stack of newspaper clippings about Maia, with extensive mathematical calculations in the margin, and the unexplained label "12.375".

Palace conjectures that the "12.375" on Zell's box is a percentage—that is, the threshold at which the chance of Maia destroying the Earth became high enough that it would be worth attempting a risky thing he'd always wanted to do: experimenting with drugs.

She discovered the theft and got her prescription pad back from her brother in October, which accounts for Zell's strange behavior at that time: he was having withdrawal symptoms.

Palace searches Toussaint's house and finds a large stash of drugs, guns, and cash hidden in the doghouse; while he is there he hears someone else flee the scene.

Naomi Eddes calls Palace with an idea: with no actuarial work left to do, Zell, like everyone else at his company, was investigating life insurance claims.

Someone who had collected on a false insurance claim would have a motive for murder (in order to avoid spending all the time left before the world ends in prison).

The toxicology screen on Zell's blood comes back and finally proves that Palace was right to suspect murder: prior to his death, he had been drugged with GHB.

From the father's behavior Palace guesses that Naomi has a history of trouble with the law, and he has a toxicology screen run on her blood: it reveals morphine sulfate.

Zell and Eddes were both killed by Toussaint's supplier: Sophia's husband, Erik Littlejohn, who has been stealing the pain medications from the hospital where his wife works.

Since the case was closed it has been announced that Maia will hit Indonesia, far away from the U.S. With the chances of post-impact survival a little higher, at least in the short term, the public mood is less gloomy.

She confesses that she used both Palace and Derek to help a group she was part of determine whether the military facility her husband was held in was in fact the one where they believe the government is working on its plans for a lunar habitat, and then leaves.

"Concord's population is well under 100,000, but it still houses the state government, it still has a decent-sized downtown, it still has a spread of neighborhoods and industries and economic classes.

That change, and Winters' request for more time to complete the book, coincided with the birth of his daughter, a break which helped him understand the character better.

[10] Shortly after the book's publication, Deadline Hollywood reported that Lorenzo di Bonaventura, producer of the Transformers movies, had optioned The Last Policeman for development as a TV series.

[3] Winters said this posed an interesting challenge for any writer since a television series would necessarily have a limited timeframe for episodes to take place.

While Winters didn't imagine a sensible movie producer trying to waste a lot of time finding a tall, gangly young actor to play Hank, in his mind he saw Jim True-Frost in the part, based on his performance as Prez in The Wire.

As stunt casting, he envisioned Tom Waits playing the police chief, who has only two short scenes in the book, "[b]ut only because I'd really, really like to meet [him].

"What's more interesting than the mystery surrounding Zell's death is Winters' vision of a pre-apocalyptic world, one where laws are both absolute and irrelevant and even minor players have major control over what could be a new future," wrote Kirkus Reviews.

While he said Winters' exploration of how people might continue on with the things they've always been doing in the face of imminent doom "adds a few hills to the psychogeography of the planet-busting asteroid trope," the rest of the book undercut its themes, especially as it starts to become apparent that Maia's impact may not be the end, after all.

Some reviewers, aware of this, appropriately noted that the Nico plotline is unresolved at the end of the novel, and her last appearance shows there might be more to her character than the story had previously suggested.

The case appears impossible given the large numbers of people abandoning their lives as the asteroid looms, but Hank is dogged in his attempts to track the man down.

It is set along the East Coast, where the breakdown of society has continued, and armed vigilante groups attempt to prevent immigrants fleeing the Indonesian impact zone from coming ashore.