DetectiveMurdochfindsthatthemanbehindaflyingmachinethatcrashesinTorontoisnoneotherthanhisoldnemesis,JamesPendrick.HelearnsthatPendrickishopingtowina$1millionprizeforthefirstcontrolledflight.Abodyisfoundintherubbleofthecrashbutsomeoneisclearlyouttostealhisinvention.MurdochalsohastodealwithOttawa-basedspymasterTerenceMeyerswhosaysit'sallanationalsecuritymatter.Meanwhile,JuliareturnsfromViennaintentonpracticingpsychiatry.She'salsohopingtohavehermarriagetoD'Arcyannulled.

MurdochandInspectorBrackenreidareaboardtheSSKeewatinaftertheowner,ClarenceMacFarlane,receiveswhathebelievesisathreat.TheKeewatinisabouttodepartfromTorontoonitsmaidenvoyagedestinedforRochester,N.Y.andMurdochthinkstheyshouldstayonboard,especiallyafterheseesthatJuliaisoneoftheinvitedguests.TheirpresenceprovesusefulafterMacFarlane'sdaughterAmy,whoisengagedtoherfather'schieffinancialofficerOwenMathers,fallsoverboardandisnowheretobefound.AsMurdochinvestigateshefindsthereisarealthreatagainsttheKeewatinandthetruefactsbehindAmy'sdisappearance.

SixmonthshavepassedsinceDr.OgdenmovedtoBuffaloandDet.MurdochisconstantlyaloggerheadswithDr.Francis,herreplacement.WhileInsp.BrackenreidthinkshighlyofFrancis,whowasrecruitedfromScotlandYard,Murdochfindshimstubbornandunimaginative.HealsoseemstobeinnorushtohelpMurdochwithhislatestcasewherehumanbodybodypartswerediscoveredonariverbankencasedincement.AhomelessmanlivinginthewoodsnearbyisquestionedandreleasedandMurdochcorrespondswithDr.Ogdenwhooffershimvaluableadviceinherletters.Healsogetshelpfromaretireddetective,MalcolmLamb.Murdochconnectshiscurrentinvestigationarapeandmurderthathadoccurredmanyyearsbefore.

MurdochisinBristol,England,withnomemoryofwhoheisandtwogunmenchasinghimthroughthestreets.WiththehelpofalocalpubLandladyhestartstopiecetogetheranassassinationplot.InTorontoDetectiveHamishSloackisassignedtohelpfindthemissingMurdoch.

SeasonfiveofMurdochMysteriesopensinunfamiliarterritory,asDetectiveWilliamMurdoch(YannickBisson)leavesTorontototryhisluckwhiletheKlondikeGoldRushintheYukonwindsdown.Suspendedforinterferinginaninvestigation,ontherunforsurreptitiouslyfreeingamurderertomakeamends,andnursingabrokenheartafterDr.Ogden'smarriagetoanotherman,hetriestoescapehispast,andhispassionfordetectivework.Backinthecity,newlypromotedChiefConstableGiles(NigelBennett)makesitcleartoInspectorThomasBrackenreid(ThomasCraig),thathe'llbekeepingaverycloseeyeonpolicematters.Meanwhile,Murdoch'sbelovedformerassociate,Dr.JuliaOgden(HélèneJoy),isnowworkingalongsideActingDetectiveGeorgeCrabtree(JonnyHarris)andDr.EmilyGrace(GeorginaReilly),afeistyyoungprotégé.Intheremotenorth,Murdochispleasedtodiscoverthathisfledglingprospectingcareermaygarnergreatsuccess,asmallcomfortafterJulia'smarriagetoanotherman.Butashetriestorebuildhislife,hefindshimselfdrawnintothecaseofMrs.ElizabethBryant(JillHalfpenny),aninnkeeperchargedwithmurder.TheplotthickenswhenwriterJackLondon(AaronAshmore)lendshisinsights,andMurdochsoonrealizesthatwhilehehadhopedtoleavehisshatteredheartandtatteredcareerbackinToronto,hisdaysasadetectivearenotbehindhim.

SetinTorontoatthedawnofthe20thcentury,MurdochMysteriesisaone-hourdramaseriesthatexplorestheintriguingworldofWilliamMurdoch(YannickBisson),amethodicalanddashingdetectivewhopioneersinnovativeforensictechniquestosolvesomeofthecity'smostgruesomemurders.Murdoch’scircleofassociatesincludesConstableGeorgeCrabtree(JonnyHarris,Hatching,MatchingandDispatching),Murdoch’seagerandoftennaïveright-handman;InspectorBrackenreid(ThomasCraig,CoronationStreet),Murdoch’sskepticalyetreluctantlysupportiveboss;andtheloveofhislife,pathologist-turned-psychiatristDr.JuliaOgden(HélèneJoy,DurhamCounty),astaunchallywhosharesthedetective’sfascinationwithforensicscienceandinnovativeideas.AllarevaluableallieswhohelpMurdochsolvehisvariedcasesandtraversethemanystratumsofVictorian-turned-Edwardiansociety.