Basil and Jon meet under unexpected circumstances when they both show up to the same probably-haunted dwelling. Basil is trying to find out whether magic and ghosts are real, and Jon is trying to disperse ghosts in-between job hunting. 

I like this as an introduction and as a story in its own right. There's a nice balance between worldbuilding and characterization, especially in such a short tale. The audiobook is excellent, conveying Jon's very dry sense of humor with ease. 

I first encountered Jon and Basil as secondary characters midway through the Inheritance series, so I was already familiar with them. I like seeing how they started out, and this novella came out before any of the Inheritance series, so it can be read before even JACK OF THORNS if one were so inclined.