In the short story Motive v. Opportunity, Grace Garrod (née Clode) is the niece of the wealthy Simon Clode. After the death of his own son and granddaughter, Simon had no living close relatives. He therefore took care of the children of a poor brother, comprising Grace and her siblings Mary and George. Some time later, Grace married a research chemist Philip Garrod and moved out although they continued to live nearby and paid frequent visits.
Grace would have inherited a third of her uncle's estate but this was disrupted by the arrival of a spiritualist medium Eurydice Spragg. Simon wanted to draft a new will to leave the bulk of his estate to this newcomer. How this is resolved forms the main plot of the story.