HenryFrankenstein(ColinClive),anardentyoungscientist,andhisdevotedassistantFritz(DwightFrye),ahunchback,piecetogetherahumanbody,thepartsofwhichhavebeensecretlycollectedfromvarioussources.Frankenstein'sconsumingdesireistocreatehumanlifethroughvariouselectricaldeviceswhichhehasperfected.

　　ElizabethLavenza(MaeClarke),hisfiancée,isworriedtodistractionoverhispeculiaractions.Shecannotunderstandwhyhesecludeshimselfinanabandonedwatchtower,whichhehasequippedasalaboratory,andrefusestoseeanyone.Sheandherfriend,VictorMoritz(JohnBoles),gotoDr.Waldman(EdwardVanSloan),hisoldmedicalprofessor,andaskDr.Waldman'shelpinreclaimingtheyoungscientistfromhisabsorbingexperiments.WaldmantellsthemthatFrankensteinhasbeenworkingoncreatinglife.Elizabeth,intentonrescuingFrankenstein,arrivesjustasHenryismakinghisfinaltests.Hetellsthemtowatch,claimingtohavediscoveredtheraythatbroughtlifeintotheworld.TheyallwatchFrankensteinandthehunchbackastheyraisethedeadcreatureonanoperatingtable,highintotheroom,towardanopeningatthetopofthelaboratory.Thenaterrificcrashofthunder,thecracklingofFrankenstein'selectricmachines,andthehandofFrankenstein'smonster(BorisKarloff)beginstomove.ThiscausesFrankensteintoshoutthefilm'smostfamousline,'It'salive!'

　　ThroughFritzdroppingabrainhewasstealingandchoosinganotherone,acriminalbrainwassecuredforFrankenstein'sexperimentswhichresultsinthemonsterknowingonlyhate,horrorandmurder.Themanufacturedmonsterdespiteitsgrotesqueform,initiallyappearsnottobeamalevolentbeast,butasimple,innocentcreation.Frankensteinwelcomesitintohislaboratory,andaskshiscreationtosit,whichitdoes.Hethenopensuptheroof,causingthemonstertoreachouttowardsthesunlight.Fritz,however,enterswithaflamingtorchwhichfrightensthemonster.ItsfrightismistakenbyFrankensteinandDr.Waldmanasanattempttoattackthem,andsoitistakentothedungeonwhereitischained.Thinkingthatitisnotfitforsociety,andwillwreakhavocatanychance,theyleavethemonsterlockedupwhereFritzantagonizesitwithatorch.AsHenryandDr.Waldmanconsiderthefateofthemonstertheyhearashriekfromthedungeon.FrankensteinandDr.WaldmanrushintofindthemonsterhasstrangledFritz.Themonstermakesalungeatthetwobuttheyescapethedungeon,lockingthemonsterinside.RealizingthatthecreaturemustbedestroyedHenrypreparesaninjectionofapowerfuldrugandthetwoconspiretoreleasethemonsterandinjectitasitattacks.WhenthedoorisunlockedthecreatureemergesandlungesatFrankensteinasDr.Waldmaninjectsthedrugintothecreature'sback.ThemonsterknocksDr.WaldmantothefloorandhasnearlykilledHenrywhenthedrugtakeseffectandhefallstothefloorunconscious.

　　HenryleavestoprepareforhisweddingwhileDr.Waldmanconductsanexaminationoftheunconsciouscreature.Asheispreparingtobegindissectingitthecreatureawakensandstrangleshim.Itescapesfromthetowerandwandersthroughthelandscape.Itthenhasashortencounterwithafarmer'syoungdaughter,Maria(MarilynHarris),whoaskshimtoplayagamewithherinwhichtheyplayfullytossflowersintoalakeandwatchthemfloat.Themonsterenjoysthegame,butwhentheyrunoutofflowers,tragedyoccurs.Duetohisdefe