The Bleak Old Shop of Stuff

What is The Bleak Old Shop of Stuff about (plot, summary)
Jedrington teams up with a seemingly charming new business partner, Harmswell Grimstone. As the Secret-Past family's fortunes rise, it looks like they are built on crumbling foundations indeed, especially when it is revealed that Conceptiva too has a secret that turns out to be even darker than Jedrington's own.