While most of Tilling thrills to Lucia's artistic accomplishments, Mapp is convinced that her summer visitor is a crashing fraud and sets out to prove it with her usual vigour. Lucia repels an early attack on her musical talent with ease and judicious use of the easier movements of Beethoven's Moonlight Sonata, and Mapp is forced to open a new front with an all-out assault on her linguistic ability. Suspecting that her tenant's grasp of Italian is limited to the few phrases she may have picked up from occasional trips to the opera, Mapp thrills to the news that Tilling is to be visited by a genuine Italian contessa. This surely will call Lucia's bluff. And when Lucia goes down with a bout of influenza on the very day of the contessa's arrival, all of Mapp's suspicions seem justified...