The Face on the Wall, by Jane Langton

Professor Homer Kelly already has plenty on his plate, when his wife Mary presents the part-time sleuth with an important task: find out why her former student Pearl Small has disappeared. Worryingly, Pearl’s husband Fred is negotiating a deal to turn the land, a former pig farm which is in Pearl’s name, into a development of McMansions.

Meanwhile, the Kellys are helping Mary’s niece Annie as she uses the windfall from her suddenly success as a children’s book illustrator to build her dream h...