TheGoldRushintheYukonandAlaskahaspromptedtheneedforbig,strongdogswhowillbeabletopullsledsovericytrails.Buck,alargeanimallivinginthehomeofJudgeMillerinSantaClara,California,isexactlywhattheexplorerswant.Heisananimalwithhuman-liketendencies,intelligence,strengthanddignity.Thusfarhehasenjoyedhiscivilizedlifewiththeoccasionalnaturestrollorhuntingtrip.Manuel,agardener'shelperwithapenchantforgamblingandaneedformoney,managestokidnapBuckandsellhimontheblackmarket.Heisgiventoasaloon-keeperandtransportedviatraintotheNorthland.Throughouttheordeal,Buckiskeptinacageandbecomesincreasinglyangry.Hemanagestobadlybiteoneofhiskidnappers.Bythetimehearrivesathisdestination,hehasworkedhimselfintoarage. 　　ThemeetingwiththeRedSweaterandthepainfulencounterswithhisclubpushBuckintosubmission.Heisnotbroken,butheknowsbetterthantokeepresisting,whichcanonlyresultinhisdeath.Onceheisbehavingcorrectly,Buck,alongwithDaveandCurly,twootherdogs,issoldtoFrancoisandPerrault,twoagentsoftheCanadiangovernment.TheymustbringthemailbetweenSkaquayandDawson,Alaska.Whileincamp,Curlyiskilledfortryingtomakefriendlyadvancestoanotherhusky.Buckunderstandsthatthisisthelawofclubandfangwhichdominatesthisnewworld.Heresolvesnevertogodowninthatmanner. 　　BuckandDavejoinapreexistingdogteamledbySpitz,abullyinghuskydog.Thetrailworkbeginsimmediately.Bucklearnsfastfromtheotherdogs.Intimehestartstobecomemorewild,losingthedomesticityimposeduponhimintheJudge'shome.TensionsdevelopbetweenhimandSpitz.Buckisreadytobealeader,andlookstousurpSpitz'spower.Whilehuntingarabbitonenight,thetwoendupinafighttothedeath.Buckachievesmastery.WhenFrancoisattemptstoplaceSol-lekattheheadoftheteam,Buckrefusestoallowit.Eventheappearanceofaclubdoesnotfazehim,forhehaslearnedhowtoavoidit.WhenFrancoisallowshimtotaketheposition,heisamazedbyBuck'sabilities.Buckbeginstodreamofanancientworldinwhichmananddogfoughtsidebysidetosurvive. 　　Aftertworoundtripsbetweentowns,thedogsareexhaustedandoverworked.FrancoisandPerraultareveryproudoftheirteam,havingjustsetarecordfortheirrun.Buttheyreceivenewordersandmustbidthedogsgoodby.SeveralScottish"half-breeds"takechargeofBuckandhisotherdogs.Hedoesnothavestrongfeelingsforthem,buttheyaregoodmenandtheycareforthedogs.Buck'sdreamsoftheancientworldgrowmorevivid.Thepathisverydifficultandmenanddogsalikearegrowingweak.OnedayDaveshowssomuchpainthatoneofthementriestogethimtorunbehindthesled.Herefusessoadamantlythatthemengiveinandallowhimtorunhimselfout.Thenextmorningtheydrivethesledaway,thenonemanreturnsandshootsDave. 　　Afterthislasttrip,theScottishmenaretoldtosellthedogsandbuyfresherones.Theteamissoldtoagroupoftenderfoots--Hal,Charles,andMercedes--lookingtostrikeitrich.Theyhavenoideahowtoworkwithadogteam.InHal'seagernesstocompletethetrail,heterriblymistreatsthedogs.Hisquietbrother-in-lawCharlesandweepysisterMercedesonlyincreasethedifficulty.Hal'sincompetenthandlingoftherationsleadsthemtorunoutoffoodforthedogshalf-waythroughthetrip.Starvingandoverworked,onebyonethedogsstarttodie.Theremna