The ninth in the series of the Bulldog Drummond adventure films based on the novels by Herman C. McNeile, this film was the only one to star John Lodge in the title role. In this outing for the daredevil sleuth, Hugh 'Bulldog' Drummond finds himself up against foreign agents who are trying to steal plans for a top-secret remote-controlled aircraft. Dorothy Mackaill co-stars as Drummond's feisty love interest, Doris.