Helsa, the exceptionally beautiful daughter of the Reverend Alfred Irvin, is thrilled when she learns that Irvin Hall, their vast ancestral home, has been rented for a large sum by a certain Lady Basset. Her Ladyship wishes to host a grand house party and has invited a number of distinguished guests including the handsome Duke of Mervinston. Helsa’s friend, Mary, agrees to play the vital role of lady’s maid to Lady Basset. But at the last minute, Mary cannot do it as she has to visit her ill grandmother. So Helsa fills in and plays the lady's maid. Helsa uncovers a dastardly plot to lure the duke into marrying against his will.