The Simpsons confide in him that they are losing a struggle with a rival heir to the estate of an eccentric clergyman named Rant, who died two decades earlier.
An inquest finds black dust on the dead man's face and in his mouth, but the real cause of death is heart failure.
When it appears that Eldred had been tearing out a page when he died, the missing will is discovered and decrypted, written in a coded script that looks like Hebrew.
On 7 May 1951, an American television adaptation of the story was broadcast as "The Lost Will of Dr. Rant", as part of the Lights Out mystery series.
It was first broadcast on the Light Programme on 28 April 1959 and received its first repeat 59 years later on 27 August 2018 on BBC Radio 4 Extra.
It starred Sacha Dhawan, John Castle, Louise Jameson, Una Stubbs, David Ryall, Eleanor Bron, Nick Burns, and Roy Barraclough.