Samuel Mullins (Anthony LaPaglia) is a church-going, doll-making, devoted dad who lives in a palatial, remote, haunting-ready home with his wife Esthe(...)

Author Roald Dahl circa 1989 with his grandson Luke Kelly, who is now the managing director of the Roald Dahl Literary Estate. Photograph: Jan Baldwin via The New York Time

The grey doorway in London’s Marylebone neighbourhood here is unmarked but for 11 words spelled out across the top rail: “The greatest secrets are alw(...)