Twentyyearsago,oldMrs.Barlowwaskilledinherhomeat12,PimlicoSquareforherpricelessrubies.Themurderersearchedthewholehousewithoutfindingthem,thendisappeared.Thehousehasbeenemptysincethen,butnowPaulandBellaMallenmoveintotheapartment.BellaMallensuffersfromforgetfulnessandnervousness-atleastthatiswhatherhusbandtellsher.Anelderlyhorsewrangler,B.G.Roughworkedasapolicemantwentyyearsagoandstillrememberstheunsolvedcase.HenoticesthatMr.MallenlooksjustlikeLouisBarre,Mrs.Barlow'snephew.AndwhydoesMr.Mallensomysteriouslyleaveeverynightjusttogointotheapartmentnextdoor,nr.14aaa