NovelistLarryDonnerBillyCrystalstruggleswithwriter'sblockduetohisresentmenttowardshisexwifeMargaretKateMulgrew,whostolehisbookandgarneredmainstreamsuccessandcriticalacclaimwithitOwenLiftDannyDeVitoisatimid,middleagedmanwhostillliveswithhisoverbearing,abusivemotherAnneRamseyOwenfantasizesofkillinghismotherbutcan'tsummonthecouragetobringhisdesiresintofruitionAsastudentinLarry'scommunitycollegewritingclass,OwenisgivenadvicebyLarrytoviewanAlfredHitchcockfilmtogainsomeinsightintoplotdevelopmentHeseesStrangersonaTrain,inwhichtwostrangersconspiretocommitamurderforeachother,figuringtheirlackofconnectiontothevictimwill,intheory,establishaperfectalibiHavingoverheardLarry'spublicrantthathewishhisexwifedead,OwenformsaplantokillMargaret,believingthatLarrywillrespondbykillinghismother
HetracksMargaretdowntoHawaiiandfollowsherontoacruiseship,apparentlypushingheroverboardwhileshetriestoretrieveanearringthatfelloutOwenreturnsfromHawaiitotellLarryofMargaret'sdeathandthatLarrynow"owes"himthemurderofhismother,lestheinformthepoliceLarrywasthekillerAfterhavingspentthenightdrinkingaloneduringthehoursofMargaret'sdisappearance,LarrypanicsbecausehelacksasufficientalibiThat,alongwithanewsreportannouncingthepolicesuspectfoulplay,convincesLarryhe'stheprimesuspectHedecidestostaywithOwenandhismotherinanattempttohidefromthepoliceLarrymeetsMrsLift,butdespiteherharshtreatmentofhimherefusestokillherEventually,whenMrsLiftdrivesOwentothebreakingpoint,Larryfinallyrelentsandagreestogothroughwiththemurder
Aftertwounsuccessfulattempts,LarryfleestheLifthomewhenMrsLiftrecognizeshimasasuspectfromanewsbroadcastabouthisexwife'sdisappearanceHeboardsatraintoMexicoand,surprisingly,OwenandMrsLiftcomealongsoastoavoidhavingtolieforhimDuringthejourney,Larry'spatiencewithMrsLiftreachesitspinnaclewhensheimpolitelygiveshimadviceonwritingHefollowshertothecaboosewiththeintentofthrowingherfromthetrain,butstopsshortwhenshealmostfallsoffonherownOwenbeginshavingsecondthoughtsabouthavinghismotherkilledandcomestohelpLarryrescueherMrsLiftisgratefulathersonforsavingher,butunappreciativeofLarry'shelpandkickshim,resultinginhimlosinghisbalance,landingonthetracks,andbreakinghisleg
Duringhisrecoveryinthehospital,LarrydiscoversMargaretisstillalive;shesimplyfelloverboardbyaccidentandwasrescuedbyaPolynesianfishermanwhomshehasdecidedtomarryMuchtohisannoyance,LarrylearnsMargaretplanstoselltherightsofherordealfor$15milliondollarsOntheadviceofafellowpatient,Larrychoosestofreehimselfofhisobsessionwithhisexwifeandinsteadfocusonhisownlife,therebyfreeinghimofhiswriter'sblock
Ayearlater,LarryhasfinishedanovelbasedonhisexperienceswithOwenandMrsLiftentitledThrowMommafromtheTrainOwenvisitsandinformshimthathismotherhasdiedofnaturalcausesandthathe'sgoingtoNewYorkCityforthereleaseofhisownbookUnfortunately,OwenrevealshisbookisalsoabouttheirexperiencestogetherThinkinghisbookhasbeenscooped,anenragedLarryproceedstostranglehim,butstopswhenOwenshowshimthebookisachildren'spopupbookcalled,Momma,Owen,andOwen'sFriendLarrywiththestorydrasticallyalteredtobesuitableforchildrenMonthslater,Larry,Owen,andLarry'sgirlfriendBethKimGreisTV版acationtogetherinHawaii,reflectingonthefinalchapterofLarry'sbookLarryandOwen'sbookshavenowbecomebestsellers,makingthembothsuccessfulwritersaswellasclosefriends
