Lettice Duffet, an expert on Elizabethan cuisine and medieval weaponry, is an indefatigable but daffy enthusiast of history and the theatre. As a tour guide at Fustian House, one of the least stately of London's stately homes, she theatrically embellishes its historical past, ultimately coming up on the radar of Lotte Schon, an inspector from the Preservation Trust. Neither impressed or entertained by Lettice's freewheeling history lessons, Schon fires her. Not one however, to go without a fight, Lettice engages the stoic, conventionial Lotte in battle to the death of all that is sacred to the Empire and the crown.