The Spare Man (by Mary Robinette Kowal)

A sci-fi, locked-door mystery set on a cruise liner heading from Earth to Mars. What a concept, right? Like Death on the Nile except in space! (Actually, it's a takeoff of The Thin Man, as you may guess from the title.) 

I was recovering from an illness as I was reading this, so it was the perfect light read for that. It's fun but flawed. The plot gets a bit chaotic and confusing (maybe moreso because I was sick) and I wouldn't classify it as a "fair play" mystery where you can figure out the answer before the end. (Although there is one twist that did have some good clues planted, and that part was satisfying.) 

Each chapter begins with a cocktail recipe to help set the stage, including zero-proof cocktails, which is a lovely touch.  There is also an adorable dog named Gimlet although knowing at least one extremely well-trained dog, the "service dog" elements of her behavior did not always ring true.  The main characters didn't do a whole lot of deducing, which is what I would have expected from a "retired detective" character.  There is a very annoying, foulmouthed lawyer who seems to have popped in from a John Scalzi novel and doesn't quite work with the tone here.

But nitpicks aside, would I read an entire series with these characters? Oh, one hundred percent, so I hope she writes more.