Vic is now married to an alcoholic lush named Thelma. But, four years ago he was involved in a relationship with New York interior designer Enid. Both have moved on, but run into each other again in Philadelphia. Pleasantries are made, awkward memories are relived, and soon Vic is cheating on his wife with Enid. The variable is Enid's good friend and neighbor Martin, a clumsy recluse that is recovering from his wife's mysterious murder. He suspects Enid and Vic are a thing, but he is suppressing desires for Enid. When Enid is found murdered, Martin is devastated and feels that Vic is the prime suspect.
Despite being released as the culprit, Vic is still Martin's number one suspect days after the murder. Only, the murder mystery becomes convoluted when Thelma (again...Vic's wife) begins having an affair and Martin finds out. Did Thelma gain her revenge by offing Vic's mistress or simply by cheating on him? As Martin digs into the clues and becomes the amateur sleuth, he finds an unlikely ally in a young woman named Rosemary, a friend of Enid's. The two begin an investigation to learn who killed Enid, but the suspect list is lengthy.
Footsteps on the Stairs is laced with all of the traditional genre tropes one would expect from a mid 20th century crime-fiction novel – numerous suspects, an amateur sleuth, clue-scavenging, and of course, the obligatory corpse. I found Martin to be a likable hero, perhaps enhanced with his mysterious past and his problematic self-awareness. His fondness for Enid is his curse, but it's a key to his own salvation as readers understand what Martin's challenges were in his prior marriage. There are a number of small intricacies that contribute to the much larger problem. How they work together is the marvel of Potts' literary work.
Whether or not this is Potts' finest crime-fiction novel is in the eye of the beholder. I have nothing to compare it to other than The Troublemaker. I endorse both novels and highly recommend the twofer. It's money well spent.