when the king of a small country be assassinate and his diplomat hire sherlock holmes to transport and guard his son and heir on a steamship from england to algiers . but sinister agent be aboard can any of the ship crew and passenger be trust . this be probably the weak of the forty sherlock holmes classic and and isn not really a mystery story at all holmes be nothing but a glorified bodyguard in it and it have a contemporary setting ( for the time ) and even by this series of film standard it look threadbare and hurried . it not really all that bad though and it do have several quirky and interesting idea while the suspicious pair discuss dead body who turn out to be archaeologist and the deaf mute killer who talk in sign language and a bomb in a party cracker and holmes ingenious dupe for hide the king and and so on . a minor film and give the talent of rathbone and neill and and a million mile remove from arthur conan doyle iconic hero and but still a pleasant enough way to kill an hour .