Dr. Sandilands, who practices in a small English city, has an elderly patient who dies, leaving him the contents of her attic. Included are sixteen battered paintings. He thinks they are junk, but a bright librarian, Stephanie du Plessis, insists that they are renaissance masterpieces. So Dr. Sandilands consults the art dealer and expert, Sir Harry Maximer. This leads to picturesque events (pun intentional) only a little less startling than the theft of the Mona Lisa from the Louvre.