In the short story The Coming of Mr Quin, Alex Portal and his wife Eleanor are guests at the New Year's Eve house party at Royston hosted by Tom Evesham which forms the main setting for the events in the story.
Mr Satterthwaite had not met Portal before the house party, but he was familiar with his family background. Satterthwaite knew Portal's father and grandfather. Satterthwaite observed that Alex ran "true to type". Like the older Portals, he was fond of sport, good at games but devoid of imagination.... what to Satterthwaite was "the usual good sound English stock". Alex is described as a man of about forty with fair hair and blue eyes.
Two years before the events of the story, Alex had been in Australia, and had met Eleanor. He had married her, and brought her home.
As events in the story unfolded, it could be seen that Alex has taken heavily to drink and that there is some tension between him and his wife. Why this is so and how this is resolved forms part of the main plot of the story.
Mr Satterthwaite observes that Alex adores Eleanor, but that sometimes he is afraid of her. He has a curious way of watching her when she is not looking.
When the guests of the house party are discussing Derek Capel's death, it is mentioned that he had been "oddly defiant" on the day of his death. Alex had not been there, but he suggests that Capel was like "a man defying Fate". Mr Satterthwaite is of the opinion that Alex himself represents a man defying Fate, and that Alex's imagination had "responded suddenly to that note in the story which recalled his own secret preoccupation".
Alex later lets the decanter slip while helping himself to whisky, and it breaks. This reminds the others of the case of Mr Appleton's death, where Mrs Appleton was seen deliberately smashing the port decanter after his death.
Alex later asks why Mrs Appleton had broken the decanter. Mr Satterthwaite suggests that she had suspected Derek Capel of killing her husband by poisoning the port in the decanter. She cared for Capel, and tried to destroy the evidence against him.
It is revealed that Alex's wife, Eleanor, was Mrs Appleton. She had told him that she had not killed Mr Appleton, but he had not quite believed her, and this was the cause of the tension between them. Alex asks her to forgive him for not believing her.