This is the fifteenth Bulldog Drummond film, and the second to be based on Herman C. McNeile (Sapper)'s novel 'Temple Tower', though the earlier film is not included in the IMDb list for McNeile, which is thus incomplete. The first filmed version of the novel was 'Temple Tower', released 13 April 1930, and starring Kenneth MacKenna as Drummond. There appears to be no surviving print of this earlier film, and no one alive has apparently ever seen it. We must presume that it is permanently lost, as the first Bulldog Drummond film, a silent of 1922, presumably is as well. Here the old gang are all back: John Howard as the perfect Drummond, Heather Angel as charming and plucky as ever as Phyllis Clavering, trying unsuccessfully for the sixth time to marry Drummond, Reginald Denny as Algy Longworth being as endearing and clumsy and twittish as ever (he breaks a Ming vase this time), H.B. Warner as the Commissioner who this time does not say 'Please don't call me Inspector!' because he is a house guest of Drummond's, as the entire action takes place at Drummond's large mansion, E. E. Clive as the inimitable gentleman's gentleman Tenny ('I try to give satisfaction, sir'), Leo G. Carroll as the dastardly and rather obvious villain Henry Seaton, and Phyllis's aunt over-played by Elizabeth Patterson (same name as my cousin who married Napoleon's brother Jerome!). (But no, Temple Tower is no relation.) The plot concerns the royal jewels having been hidden by a royalist colonel during the Civil War of 1642-5 in the cellars of Temple Tower of Drummond's own family mansion. An absent-minded professor has figured this out, and travelled all the way from the British Museum Library with the royalist's original diary in his bag, including maps of tunnels and a mysterious cipher, to discover the treasure which he has calculated is 'worth a million pounds' (in 1939 money). This is a typical comedy thriller, of the type soon coming to an end. One more would be made with John Howard before the War put an end to all this fun ('Bulldog Drummond's Bride', released four months later). We are nearing the end of an era, and this kind of jollity (piping oboes when people make funny faces, Algy falling down the stairs entangled in a suit of armour in the dark, the occasional witty line delivered with old-fashioned applomb) would soon vanish like smoke, as the dogs of war were unleashed and howls of laughter were replaced by howls of anguish of the murdered and the bombed.