A typical interim serial, the ten-chapter Ace of Scotland Yard was released in both a silent version and as a part-talkie. Dignified British actor Crauford Kent played Angus Blake, a retired Scotland Yard investigator who becomes involved in a tug-of-war between two desirable women, the virginal Lady Diana Blanton (Florence Allen) and the nefarious Queen of Diamonds (Grace Cunard), a female master criminal out to steal a valuable ring belonging to Lady Diana. In his attempts to protect both Lady Diana and her gem, Blake encounters, among other perils, a handsome but deadly foreign prince (Albert Prisco), an ancient Egyptian mummy, and a near death experience in the Gobi desert. Ace of Scotland Yard was a sequel to Blake of Scotland Yard (1927), which had starred Hayden Stevenson as Blake, Gloria Grey as Lady Diana, and Grace Cunard as the mysterious "Lady in White." The relative success of Ace probably persuaded Universal mogul Carl Laemmle to order the first all-talkie serial The Indians Are Coming (1930).
by Hans J. Wollstein synopsis