''The Flood'' is the second ''{{Franchise/Halo}}'' book, a novelization of ''VideoGame/HaloCombatEvolved'', by William Dietz. It goes into detail about not just John's escapades during ''Halo 1'', but the ODST, Marines, and [[PerspectiveFlip the Covenant]] during the events of the game.

Not to be confused with TheGreatFlood, although [[RuleOfSymbolism the allusion is intentional]].
!!Tropes used in the novel:

* AdaptationExpansion[=/=]AllThereInTheManual: Ever wonder what the Marines were up to during the game? Now you know. Most of their time is spent recovering supplies and vehicles back from the Pillar of Autumn in large battles, taking prisoners, and trying to find another way offworld.
** The Elite (or one of the Elites) who ambushes you during The Maw was obsessed with killing you the entire time.
** Now you know how Keyes got captured by the Covenant and why [[spoiler:his bridge crew is missing from every other book, or the game.]]
* AndIMustScream: If you thought [[spoiler:Jenkins' and Keyes']] fates were bad, wait until they're given detail here. [[spoiler:Jenkins' Infection pod was starved too long and didn't completely consume Jenkins' mind, leaving him free to witness him killing and mutating and feeling the pain he takes from the mutations and gunfire, and Keyes has his memories - eventually his very personality - torn from him as the Gravemind tries to find Earth.]]
* AFatherToHisMen: Major Silva, Captain Keyes, and surprisingly, the Prophet residing the operation on Halo ([[OffWithHisHead except]] [[YouHaveFailedMe when they fail him]]).
* AGlassOfChianti: Major Silva jokes about the ODST not getting the wine in the officers' drop pods. Turns out, they actually have wine in them (Keyes is about to get some before noticing a cloaked Elite trying to kill him).
* BadassNormal: Sergeant Marvin Mobuto, who was Spark's ''first'' attempt to get someone to get through the Library. He managed to make it pretty far in before getting killed, and he wasn't a SPARTAN or other super soldier, he was just a regular guy. The Chief makes it a point to show his respects to this soldier who he never met but was able to survive this long in the Library.
* BittersweetEnding: to Wallace Jenkins' story; he's finally able to receive [[spoiler: a MercyKill from McKay and dies thanking her.]]
* ButtMonkey: ''Yayap''. A Grunt who had the misfortune of encountering and surviving John, gets shackled with an overzealous idiot Elite, is beaten up and taken prisoner, and gets [[spoiler:front-row seats to Halo exploding.]] And, of course, the Grunts as a whole.
* ContrivedCoincidence: Out of all the Flood forms McKay could have chosen to take prisoner, she decides to take the one inhabited by a half-living human desperately wanting to die. Similarly, the novel goes into great detail into ''why'' Jenkins kept some form of his mind after being assimilated - the Flood Infection pod that hijacked him was too starved to make a complete override.
* DisproportionateRetribution: At one point, Ensign Dowski decides suggesting to Keyes to surrender to the Covenant, while being really insubordinate about it. Granted, this is one of the stupidest things anyone has said in Halo, but it's followed by Keyes ''tying her up and leaving her to be killed by the Covenant.''
* DownerEnding: Other than Master Chief's story, [[spoiler:the Marine subplot ends with nearly all the Marines dying on Halo, due to Silva's decision to bring a Flood-infested ship directly to Earth and [=McKay=] deciding that the Flood infection risk is far too great and severing the ship's controls, killing all hands on board.]]
* FantasticRacism: Jackals hate Grunts, and abuse them at every opportunity.
* FictionalDocument: The 2010 rerelease to celebrate the launch of ''VideoGame/HaloReach'' includes a series of documents and transcriptions further expanding on the EU.
* FunetikAksent: The Spec Ops Elite following the evacuating Pillar of Autumn's bridge crew has no idea who this "Keezz" person is, but he sounds important. He winds up getting headshot by "Keezz", who is, you guessed it, Keyes.
* GenderBender: An ODST called Parker accompanies John on his mission to rescue Captain Keyes; they change from a he to a she between scenes. This was fixed in the 2010 edition, in which Parker is a male throughout.
* GloryHound: Major Silva [[spoiler:nearly gets the human race infected with the Flood, thanks to this. He tries to bring home a Covenant ship, with Flood pods on it, to gain himself and the [=ODSTs=] recognition and awards.]]
* HeAlsoDid: Ten years later, the author would infamously write ''Literature/MassEffectDeception''.
* HeroicAlbino: Not exactly, but a Marine accompanying John to Major Silva notes how pale he is from all the time spent in the suit.
* MajorlyAwesome: Silva is well respected amongst the [=ODSTs=] and is considered AFatherToHisMen.
* ProudWarriorRaceGuy: '''Zuka 'Zamamee'''. Even more so than other elites (and this is from the Elites, a race full of them). Even his superiors tell him to knock it off at times.
** The [=ODSTs=], especially Major Silva, who hates John for [[Literature/HaloTheFallOfReach killing four of his best men a few years back.]]
** Tellingly, this status gets them [[spoiler:both killed. 'Zamamee is fragged by John without much of a fight, and Major Silva nearly dooms the entire human race by bringing a captured Covenant ship directly back to base in breach of the Cole Protocol (a Covenant ship had never been captured before, and he believed it'd bring him and the survivors, but especially the ODST, fame) with Flood still on it. If the Covenant didn't track them back to Earth, then the Flood would have consumed it.]]
* QuintessentialBritishGentleman: Wellsey, the other AI aboard the ''Pillar of Autumn''. Actually pretends to be the Duke of Wellington, down to his appearance, mannerisms, and insisting that he was there at his actual victories, which annoys his acquaintances.
* RetCon: One of the Elites makes an exception to the Covenants' refusal to absolutely use human weapons by snapping up a pistol and [[spoiler:executing Hikowa.]] Though said Elite immediately threw away the pistol after firing that one bullet because his finger was too large to fit comfortably in the trigger guard, contemptibly declaring it 'primitive'.
** More importantly, the 2010 rerelease changes a number of details to make the book mesh better with later canon, as well as to simply fix internal inconsistencies.
* RewardedAsATraitorDeserves: The naive Ellen Dowski insists that they surrender to the Covenant and receive mercy rather than keep fighting and all be killed. When the bridge crew abandons her so only she alone can surrender, [[spoiler:she deliberately leaks their location to the Covenant when interrogated to prove she's right. However, after capturing the rest of the bridge crew the Elite in charge systematically kills them off. Ellen protests about this in shock, only for the Elite to kill her too.]]
* ScrewThisImOuttaHere: Yayap, after failing to talk Zuka out of his suicidal quest to kill "the demon" (John), finally gives up and steals a Ghost to find a way off Halo. [[spoiler:Unfortunately, he gets first-row seats to the Pillar of Autumn detonating Halo.]]
* SuddenDownerEnding: [=McKay=], Silva, and hundreds of other marines manage to take over the ''Truth and Reconciliation'', and are about to leave Halo... [[spoiler: when Silva firmly grasps the IdiotBall to force the ending to be an IdiotPlot; he decides he wants to take Flood samples with him, despite the warnings of Wellsley and [=McKay=]. Even worse, he doesn't plan on containing them before taking off, being convinced that his people can save that part for afterwards. Instead of either continuing to try and talk Silva down, or even assassinate him and hope (perhaps vainly) that saner minds prevail, [=McKay=] blows up the entire ship, killing everybody on board. This is probably because they were all DoomedByCanon anyways]].
** The sad thing is, [[spoiler:even if Silva had ordered a full decontamination before takeoff, this trope might have still applied anyways, given that they had almost no time left before the ''Autumn'' blew up and took Halo with it]].
* SuddenSequelDeathSyndrome: Keyes' [[spoiler:handpicked bridge crew]] from ''Literature/HaloTheFallOfReach'' are unceremoniously shot in the face when a Covenant dropship gets the drop on their crashed lifepod.
* TheOnlyOneAllowedToDefeatYou: Zuka 'Zamamee, a Special Ops Elite who survived an encounter with John, tries his damndest to get approval to pursue and kill "the Demon". [[UnknownRival Not that John knows.]]
* UnknownRival: Zuka 'Zamamee to John, who is the nameless elite (or one of them) you kill during The Maw.
* WritersCannotDoMath: On the opening page, no less. Sam Marcus is mentioned as getting his first sleep cycle in 36 hours; he'd most likely be useless at his job if was given a 36 hour shift, as it is insanely long. Even worse, it's mentioned he's only managed to get three hours of sleep since the Pillar of Autumn made a slipspace jump, which was twenty days ago. He's got three hours of sleep in twenty days, yet he's only portrayed as being a bit tired instead of, y'know, ''dead''.
* ZombieApocalypse: The Flood.