-> '''Laurie Strode''': You've heard the story?\\
'''Will Brennan''': Who hasn't? Michael Myers. It's like 20 years ago?\\
'''Laurie''': 1978.\\
'''Will''': And the girl that...what happened to the sister, she died, right?\\
'''Laurie''': No, she faked her death... and now, she's the headmistress of a very posh, secluded private school in Northern California -- hoping and praying every year...that her brother won't find her.

Ignoring the continuity of the [[Film/Halloween4TheReturnOfMichaelMyers last]] [[Film/Halloween5TheRevengeOfMichaelMyers three]] [[Film/HalloweenTheCurseOfMichaelMyers films]] of the ''Franchise/{{Halloween}}'' franchise, ''Halloween [=H20=]: Twenty Years Later'' picks up the story of FinalGirl Laurie Strode (Creator/JamieLeeCurtis). After faking her death to live in peace following the horrific events during the [[Film/{{Halloween 1978}} Halloween night of 1978]], Laurie had changed her name to Keri Tate, had a son, and became a headmistress for a high school far away from Haddonfield, Illinois.

Michael Myers, however, has finally tracked Laurie down, and after two decades of waiting, he comes back into her life -- and enters the lives of a number of students, including Laurie's son -- in order to kill her once and for all...
!! ''Halloween [=H20=]: Twenty Years Later'' contains examples of the following tropes:

* ActionGirl: Laurie has had enough of Michael's bullshit.
* AdvertisedExtra: Creator/JosephGordonLevitt, [[spoiler:whose character died in the opening scene]].
* AndStarring: There is "introducing Josh Hartnett". He has done quite well for himself ever since.
* BallsOfSteel: Michael takes a knee to the groin, but barely reacts.
* BigEater: Sarah. While preparing a massive amount of junk food for a Halloween party, she mentions she's got such an intense love of food that it's actually a goal of hers to get fat.
* BloodyHandprint: Laurie leaves a bloody handprint on the door of a closet, tricking Michael Myers into thinking she was hiding inside.
* CallBack: Michael [[spoiler: lifting Will up with his knife after stabbing him]] is reminiscent of the infamous scalpel scene from ''Film/HalloweenII1981''.
* CampingACrapper: Averted. A woman and her daughter go to a public bathroom and Michael Myers follows them in. After a tense scene in which the audience assumes he is going to kill them, he ends up stealing the woman's car keys instead.
* CanonDiscontinuity: Everything that came out between ''Halloween II'' and this.
* CarFu: Laurie hijacks an ambulance van with Michael in it, and runs it off a cliff in order to kill Michael once and for all.
* CaughtInASnare: Laurie has a snare trap set for Michael.
* CelebrityParadox: One of the college students watches ''Film/{{Scream 2}}''. Even though the first ''Film/{{Scream|1996}}'' showed ''Film/{{Halloween|1978}}'' being played.
* CharacterDevelopment: Laurie Strode, who goes from a DamselInDistress to a badass ActionGirl in this movie! She even provides the page image!
* DangerousKeyFumble: Molly does this as Michael closes in.
* DepartmentOfRedundancyDepartment: The subtitle, considering on how ''[=H20=]'' already means that it has been twenty years from the first film's events.
* EvilOverlooker: The poster had Michael Myers' BlackEyesOfEvil looming over the frightened-looking protagonists.
* {{Foreshadowing}}: Laurie is teaching an English literature class on Mary Shelley's novel ''Literature/{{Frankenstein}}''. Molly, one of the students, responds to a question about the book and fate with this:
-->"I think that Victor should have confronted the monster sooner. He's completely responsible for Elizabeth's death. He was so paralyzed by fear that he never did anything. It took death for the guy to get a clue."'' She goes on to say that Victor finally confronts the monster because he ''"had reached a point in his life where he had nothing left to lose. I mean, the monster saw to that by killing off everybody that he loved. It was about redemption. It was his fate."
** This foreshadows the final scenes in the movie where [[spoiler:Laurie finally decides to stop running from Michael Myers and confront her monster. After twenty years of living in fear and seeing her loved ones murdered, she had nothing more to lose. It was time to face her fears and end the nightmare]].
* GenreSavvy: Laurie's not willing to take the chance of Michael coming back again, so [[spoiler: she steals the ambulance taking away his body and cuts his head off]].
* GroinAttack: Laurie knees Michael in the groin. [[BallsOfSteel It doesn't do anything except cause him to give her a nasty glare]].
* TheHunterBecomesTheHunted: At the end Laurie turns the tables on Michael Myers and starts hunting him down with an axe.
* MamaBear: In the original movie, Laurie had no qualms attacking Michael in self defense. In H20, she really lets him have it when he attacks her son.
* NonchalantDodge: Michael's response to Laurie's knife throwing act.
* OffWithHisHead: [[spoiler:Laurie beheads Michael in the end. The next film [[DeathIsCheap changed this greatly]].]]
* OddlyNamedSequel2ElectricBoogaloo: No, the movie is not named after the chemical formula for water (H20 = Halloween 20 Years Later). Although, water has a PH of 7.0. And this is the seventh movie in the ''Halloween'' franchise.
* ProlongedPrologue: The prologue goes for almost 20 minutes before the opening credits begin.
* SassyBlackWoman: Ronnie's wife.
* SayMyName: Laurie after she starts hunting Michael:
* ShoutOut: One character is named Norma Watson after PJ Sole's role in the first film adaptation of ''Film/{{Carrie|1976}}''. Soles also played Lynda in the original ''Halloween''.
** There is also a cameo by Janet Leigh, mother of Jamie Lee Curtis and star of ''Film/{{Psycho}}'', which is the Spiritual Ancestor to the original ''Halloween''. Janet Leigh drives the car she drove in Psycho, and her scene is scored with the music from that film.
* StalkerShrine: It is revealed that Dr. Loomis' office is a shrine to Michael Myers, with three decades worth of newspaper clippings about Myers taped all over the office walls. To add to the creepiness, he also has high school photos of Laurie (Michael's sister) stuck to the wall too.
* SuddenSequelDeathSyndrome: [[spoiler:Marion Whittington and Doctor Loomis. Actor Creator/DonaldPleasence [[TheCharacterDiedWithHim did sadly pass away]] in 1995. At least his death was [[KilledOffScreen off-screen]] unlike Marion unfortunately.]]
* TookALevelInBadass: Laurie.