''The Wheel of Darkness'' is a novel by Douglas Preston and Lincoln Child first published in 2007. It is part of their informal [[Literature/AgentPendergast Agent Pendergast series]].

After her ordeal at the hands of Diogenes in ''Literature/BookOfTheDead'', Pendergast takes Constance on a world tour to introduce her into the modern world and hopefully heal her wounds. They end their journey at a Tibetan monastery, where Constance is schooled in the same meditation techniques Pendergast has mastered. While there, the monks reveal a devastating loss of an ancient artifact designed to cleanse the world of humanity's evils. They implore Pendergast to retrieve it and return it to their protection. Pendergast tracks the artifact to the maiden voyage of the ocean liner Britannia, where it's evils are released on four thousand people trapped in the middle of the Atlantic Ocean.

!!This novel provides examples of:

* ArtifactOfDoom: The Agozyen. [[spoiler: A Tibetan painting that turns anyone who looks at it into a monstrous sociopath]].
* BaitTheDog: So, you have Captain Mason, whose dealing with a serial killer that's slaughtering one passenger every night, and she's attempting to take command of the Britannia to divert it to the nearest port to prevent any future deaths. Sounds like a really admirable person to root for, right? [[spoiler: It turns out she's ''not only behind all the killings in the first place'', but is trying to commandeer the Britannia to destroy it even though it'll kill everyone else on board.]]
* BlueAndOrangeMorality: The tulpa.
-->'''Constance''': So it was an agent for good in the end.
-->'''Pendergast''': One could say that--although I doubt goodness is a concept that it would either understand or care about.
* BookEnds: Pendergast and Constance at the temple [[spoiler:and discussing Constance's pregnancy]].
* BrownNote: The Agozyen either drives everyone who sees it insane, or turns them into monstrous sociopaths.
* ChekhovsGun: The monk tells Constance about the power to create and manipulate objects through meditation. [[spoiler:The Agozyen gives it's viewer the power to do these things]].
* TheChosenOne: [[spoiler:Constance's child]] is the reincarnation of the lama.
* EnlightenmentSuperpowers: [[spoiler: The powers granted by the Agozyen are an evil variant of this.]]
* DirtyCoward: When things start to go south, Mayles abandons his duties and sneaks off to the lifeboats to save his own skin.
* EldritchAbomination: The tulpa.
* FaceHeelTurn: [[spoiler: Pendergast undergoes one after being exposed to the Agozyen, which causes him to turn his back on humanity and attempting to leave everyone on the Britannia to die, and while also trying to make Constance give up her own morals]].
* GaiasVengeance: The Agozyen is designed to wipe the evil of humanity [[spoiler: [[SelfFulfillingProphecy by turning anyone who looks at it evil]]]].
* GoodGirlsAvoidAbortion: Constance visited an abortion clinic between the end of ''Literature/BookOfTheDead'' and the beginning of the novel. [[spoiler:In the end, she reveals she couldn't go through with it]].
* HeroicSacrifice: [[spoiler:Bruce]] offers to test the lifeboats to see if they can be safely released in the conditions. [[spoiler:They can't]].
* HoistByHisOwnPetard: [[spoiler: Pendergast turns the tulpa back on Blackburn]].
* HowUnscientific: [[spoiler: Generally, the fantastical elements of the Pendergast novels fall in the realm of mild ScienceFiction. However, the events of this novel include truly supernatural elements, such as the tulpa. At the end Pendergast explains that it's just something modern science hasn't figured out yet.]]
* IKnowYoureInThereSomewhereFight: [[spoiler:When Pendergast is warped by the Agozyen, Constance has him meditate with her to try and free his mind from the evil]].
* TheKillerInMe: [[spoiler: Mason has been attempting to stop the murders on the ship. Blackburn, who's already been confirmed to be behind the Agozyen theft, looks to be the suspect. Turns out Mason's the killer and she's been using the murders as a cover to start a mutiny and take over the ship.]]
* MoralDissonance: Upon finding out the nature of the Agozyen's function [[spoiler: Pendergast returns it to the monks after recovering it instead of destroying it]].
* NiceToTheWaiter: The Brittania is full of wealthy and influential passengers. You can tell the good from the bad by how they treat the staff.
* NotTooDeadToSaveTheDay: [[spoiler: ''Diogenes'' of all people does this, saving his brother from the tulpa and helping to snap him back to normal after his exposure to the Agozyen.]]
* PowderKegCrowd: When the crash becomes imminent, panicked passengers gather at the lifeboat hatches. When they think the crew is abandoning them they turn into a mob and force their way in.
* PrettyLittleHeadshots: Averted. The shot to the forehead that killed [[spoiler: Jordan Ambrose]] is described realistically.
* ProfessionalButtKisser: As cruise director, Mayles' job is to suck up to the rich passengers.
* SelfFulfillingProphecy: The Agozyen's method of cleansing the Earth of [[HumansAreBastards Human Evil]] [[spoiler: is to turn anyone who looks at it into an OmnicidalManiac]].
* SequelEpisode: In a way, this novel is one to ''Literature/BookOfTheDead'' [[spoiler: resolving the plot of Diogenes's child with Constance.]]
* StayInTheKitchen: Mason is clearly the superior officer over Cutter but she is relegated to the captaincy beneath him as commodore. The only reason for this is her gender. [[spoiler:The Agozyen releases her anger about this and she attempts to sink the Britannia in retaliation]].
* WhatTheHellHero: [[spoiler: After Pendergast gets a new change in attitude, Constance repeatedly states that what he's doing now goes against everything he's believed in in the past.]]