The House of the Poplars

A man walks into a bar with a bottle of his wife's sleeping pills in his pocket and twenty thousand pounds' worth of desperation in his chest.
He walks out with rather more than he bargained for. 
The house at the end of the poplar avenue is waiting. And the gentlemen of Smith & Smith are nothing if not thorough.
A chilling tale of greed, calculation, and consequences from one of the great masters of Golden Age crime.
Dorothy L. Sayers at her most quietly devastating.