Mr. Monk in Trouble

Adrian Monk and Natalie Teeger are celebrating Halloween in Monk's apartment – Monk by handing out disinfectant wipes instead of candy, and Natalie using what little time she can get to relax (the rest stopping Monk from insulting any trick-or-treaters who dare come to his door). When a young man tries to trick-or-treat dressed in bloody clothing and carrying a knife, Monk knocks him out and tells Natalie he's not in costume – he really has just committed a murder. Natalie ties up the man and calls Captain Stottlemeyer, who shows up in a pirate costume. Randy, dressed as Dirty Harry Callahan, scopes Monk's neighborhood and finds a woman who lives just a few houses down from Monk stabbed to death on her kitchen floor. Monk claims his visitor is the woman's boyfriend and he killed her during an argument. The visitor denies this, but Stottlemeyer arrests him anyway.

The next day, Stottlemeyer sends Monk and Natalie to Trouble, California, a small town known for an unsolved train robbery that happened there in 1962, to investigate the murder of a museum security guard who was a retired San Francisco police officer. There, Natalie falls in love with the police chief, Harley Kelton. The two then investigate and discover that in the 1840s, Trouble was also home to one of Monk's distant relatives, an assayer who possessed skills invaluable to the small town, and exhibited many of the same obsessive compulsive traits as Adrian. Monk discovers that these seemingly uncorrelated historical facts are connected to the murder. However, Chief Kelton says the murder has already been solved – he's positive an ex-con named Gator Dunsen is responsible. The trio stake out Gator's house, attempting to arrest him, but he fires upon them and is killed in the ensuing shootout. Kelton is reprimanded for trying to apprehend Gator without backup, and Monk and Natalie instead try to question Clifford Adams, the engineer of the train that was robbed. But when they arrive, they find Clifford murdered, and when they try to go for help, Monk falls into a mine shaft, and Natalie dislocates her shoulder when pulling him out.

Natalie is treated and confined to bed, during which Monk solves the case. Believing Monk to be in danger, Natalie takes Chief Kelton to the museum, where Monk has confronted mechanic Bob Gorman, who he claims is the killer. However, when he spots Natalie, he yells that Kelton is Gorman's accomplice.[3]

Here's what happened

The gold from the robbery was melted down and used to line the train's furnace, which the robbers were planning to retrieve afterward as the train was supposed to be scrapped after that fateful run, but the robbery's publicity allowed the train to remain in business, and they never got the chance. When Kelton and Gorman discovered the truth, they plotted to steal the gold for themselves. Gorman killed the guard to replace him and make it easier for himself and Kelton to gain access to the train. However, they needed a scapegoat to get the investigation closed as soon as possible, so they used Gator. The duo drugged Gator and tied him up before Kelton went to tell his theory about Gator to Monk and Natalie, and the shots from inside the house were actually fired by Gorman, who shot Gator and untied him just before he fled the house. But Clifford found out what the duo was up to, so Kelton killed him to keep him quiet.

Kelton holds Monk and Natalie at gunpoint, preparing to kill them and stage their deaths to appear accidental, but Monk has secretly contacted Stottlemeyer, Disher, and the state police, who emerge from hiding. The state police arrest the duo and relieve Kelton of his position, while the gold is recovered as a separate display for the museum.

The next day, Natalie berates Monk after he admits to using her to lure Kelton to the museum in order to expose his involvement, and forces him to apologize by throwing French fries at him. Stottlemeyer and Disher arrive to inform Monk that the state police have not only confirmed his theory but also discovered that the two murders Gorman committed were under Kelton's orders; thus, Kelton will be charged with all three, while Gorman has made a deal to testify against him.

The novel featured a short story entitled The Case of the Piss-Poor Gold, which was published before the novel was released in the November 2009 issue of Ellery Queen's Mystery Magazine.[4] In the story, Artemis Monk, an assayer in the California gold rush town of Trouble in the 1840s, goes from determining the value of rocks to solving a murder.