MorseandLewisinvestigatethedeathofLauraPoindexter,anAmericantouristwhoispartofanexclusivetourgroupvisitingOxford.Missingfromherpersonaleffectsisherjewelry,includingtheWolvercoteTonguewhichshewasgoingtodonatetotheAshmoleanMuseum.Thepathologistdeterminesthatshediedofnaturalcauses,butMorsefeelsthere'ssomethingnotquiteright.ThemysterydeepenswhenTheodoreKemp,theAshmolean'sexpertontheWolvercoteTongue,isfounddeadandMrs.Poindexter'shusbandgoesmissing.