Poor but intelligent Emily Fox Seton accepts a marriage proposal from the older Lord James Walderhurst, a widower pushed into providing an heir by his haughty aunt Maria.
When an old castle needs repairs, it's time to call Bob the Builder! Unfortunately a case of mistaken identity puts Bob's father in charge, resulting in one disaster after another! Meanwhile, tales of Camelot inspire Bob's noble crew of machines - Sir Lift-A-Sot, Sir Roll-A-Lot and Lady Mix-A-Lot -...