When Mary Russell is called upon to investigate the criminal activities that surround England's silent-film supremo Randolph Fflytte, she finds herself travelling undercover to Morocco, as chaperone to the stars of his latest extravaganza, Pirate King, based on Gilbert and Sullivan's masterful The Pirates of Penzance. Nothing seems amiss until the cameras start to roll and Mary feels a storm of trouble brewing... a derelict boat, a film crew with secrets, ominous currents between the pirates, decks awash with budding romance - and where is her husband Sherlock Holmes? As film fiction becomes true terror, Russell and Holmes themselves may experience a final fadeout...