When the curator declines his gift of the knocker to the museum, Ben screws it to his own front door. Consequently he is woken in the night to find that he is, momentarily, in Geap Manor, witnessing Widdowson's rites, and realizes that his house is built on the site of the manor. He gets rid of the knocker and returns to the museum to find that it has been closed for some time and no-one has heard of the curator. The next night the knocker mysteriously re-appears, placing Ben and his pregnant girl-friend at the mercy of the ghost of the childless Widdowson.
—don @ minifie-1