Past imperfect. Julian Fellowes. 2008.

Damian Baxter is very rich and dying. He lives alone, attended by chauffeur, butler, cook and a housemaid, a life of everything and nothing. Before he goes he needs to know if he has a living heir. At stake is his fortune of £500 million. By the time he married he was sterile, but what about before then?  Had he fathered a child? An anonymous letter suggests so. But finding the truth will not prove easy, as the only man who knows where to look is Damien’s sworn enemy.