Morsefindshimselfthesubjectofamurderinvestigationwhenhisfriend,BerylNewsome,ismurderedatarehearsaloftheMagicFluteandhefoolishlytouchesthemurderweapon.MorseissuspendedandDCIBottomley,withDSLewisassistinghim,isputinchargeofthecase.Morsefeelsthathewasset-upandlookstohispasttoseewho,amongthemanycriminalshearrested,mightnowbesettingaboutseekingrevenge.Whensomeonescratchesmasonicsymbolsalloverhiscarandheisreportedforerraticdriving,MorsewondersifMasonsmaysomehowbeinvolved.WhenalargenumberofhispersonalitemsarefoundinBeryl'sapartment,Morseisplacedunderarrest.