NewYorkprivatedetectiveDuncanMacMacLainisblindbuthaskeenlydevelopedallhisothersenses.HepursueshisworkassistedbyhisfaithfulguidedogFriday,hisbutler,Alistair,andhisassistant,Marty.RetiredactressNormaLawry,anoldfriend,comestoMacseekingadvice.Herheadstrong17-year-oldstep-daughterBarbara,herselfapromisingactress,isenamoredwithherleadingmaninasmalltheaterproduction,themucholderLotharioPaulGerente.Paul,whohadoncebeenNorma'slover,hasconvincedBarbarathatNormaactuallywantsPaulforherselfandhasonlymarriedherfatherStephenforhismoney.AtMac'surging,NormatriedtoreasonwithPaul,butheinsiststhathelovesBarbaraandlaughsheroff.BarbaraisequallydisdainfulofherandagreestomeetPaulfordinnerthatnightathisapartment.　　Norma'shusbandStephenLawryisascientistleavingthatnightonatriptotestasecretinventiononwhichhehasbeenworkingforthegovernmentandthewareffort.WorriedaboutBarbara,sheusesapretextnottoaccompanyStephenandgoestotheapartment.WhenBarbaraarrives,shefindsPaul'sdeadbodyandth