A third series was planned, but was cancelled before production began. As a result, the story never arrived at its logical conclusion. The programme stars Karl Howman as the mysterious Mulberry, a man who appears at the household of a cantankerous spinster, Rose Farnaby, and applies for a position as her manservant. Miss Farnaby's other staff, Bert and Alice Finch, are immediately suspicious, as the position for which Mulberry applies had not yet been advertised. Their suspicions are well placed.