美国空军将领杰克•瑞（斯特林·海登SterlingHayden饰）怀疑苏共的“腐朽思想”正在毒害“正直善良”的美国人民，他于是下令携带核弹头的飞行部队前往苏联，对敌人进行毁灭性的核打击。苏联方面得知此事，立即致电美国总统墨尔金•马夫雷（彼得·塞勒斯PeterSellers饰），并威胁如若领土遭到攻击，苏联将不惜一切代价按下“世界末日装置”。该装置的威力足以摧毁地球上所有的生命。

Onarainynightin1928inaPennsylvaniafactorytowncalledIverstown,MarthaIvers(JanisWilson),thirteenyearsold,istryingtoescapefromtheguardianshipofherwealthy,domineeringaunt.Herfriend,thestreet-smart,poorSamMasterson(DarrylHickman),comesforherthroughherbedroomwindow,butMartha'sauntcatchesthem.WhileSamslipsoutunnoticed,MarthahitsMrs.Iversonthehead,causinghertofalldownthelongstaircaseanddie.ThoughSamsawnothing,theeventwaswitnessedbyWalterO'Neil(MickeyKuhn),thesonofMartha'stutor(RomanBohnen),knownasMr.O'Neil.MarthaliesabouttheincidenttoMr.O'Neil,andWaltersupportsher.[5]　　Mr.O'NeilsuspectswhathappenedbutpresentsMartha'sversionofeventstothepolice,thatanintruderisresponsible;hemakesuseofhisknowledgebyhavinghermarryhisson.Whenthepoliceidentifyaformeremployeeoftheauntasthemurderer,thetwoO'NeilsandMarthahelpconvicthim;heispunishedbyhanging.[5]　　Eighteenyearslater,theolderO'Neilhasdied.Walter(nowplayedbyKirkDouglas)isthedistrictattorney,whileMartha(BarbaraStanwyck)hasusedherinheritancefromheraunttobuildalargebusinessempire.Theirmarriageisone-sided;helovesher,butshedoesnotlovehim.　　Sam(VanHeflin),nowadrifterandgambler,stopsinthesmalltownbychancetohavehiscarrepairedafteranaccident.Whilewaitingforrepairs,athisoldhome,nowaboardinghouse,hemeetsAntoniaToniMarachek(LizabethScott),whohasjustbeenreleasedfromjail.Sheislaterpickedupforviolatingherprobationbynotreturningtoherhometown.SamgoestoseeWalter,toseeifhecanusehisinfluencetogetherreleased.　　WalterisconvincedSamhasreturnedwithblackmailinmind,givingWalteramotivetorunSamoutoftown.WhenMarthareactswithjoytothenewsofSam'sreturn,Walter'sjealousyprovidesanadditionalmotive.WalterforcesTonitosetSamup.Samisbeatenanddrivenoutoftown,butheistootoughtobeintimidated.Whenallelsefails,Waltermakesahalf-heartedattempttokillSamhimself,butiseasilydisarmed.Marthatheninadvertentlyblurtsoutthecouple'sfearsofblackmail,whichprovetobegroundlessSamsayshedidnotwitnessthedeath.Marthabreaksdownandlamentsthatheleftwithoutherallthoseyearsago,takingwithhimheronlychanceforloveandfreedom.　　Samistornbetweenhisoldloveandhisnew.AlthoughheeventuallyforgivesToniforbetrayinghim,heandMarthaspendanidyllicdaytogether,rekindlinghisfeelingsforher.　　WalterarrangestomeetSamtofinallysettlematters.BeforeSamarrives,WaltergetsdrunkandMarthafindsoutaboutthemeeting.WhenWalterfallsdownthestairsandisknockedunconscious,MarthaurgesSamtokillhim.SaminsteadbringsWalteraround.MarthapullsoutagunandthreatenstoshootSaminselfdefenseasanintruder.However,SamgamblesthatWalterwillnotbackupherstory;heturnshisbackonherandleaves.　　Walterembracesandkisseshiswife;thenhepointsthegunathermidriff.Oddlyrelieved,sheputsherhandoverhishandonthetriggerandpresses.Assheisdying,shedefiantlystateshernameisnotMarthaIvers,butMarthaSmith.Outside,Samhearstheshot.Herunsbacktowardthemansion,butseesWalter,holdingMartha'sbody,shoothimself.SamandTonidriveawaytogether.