The extraordinarily wealthy Tesla Crane and her husband are incognito on their honeymoon cruise. Not only did she inherit the company responsible for Earth's telecommunications, but she was a brilliant robotic engineer whose career ended in tragedy, leaving her broken in both mind and body. A few days after the ship begins its journey from the Moon to Mars the newlyweds interrupt a murder outside their cabin. Being a famous detective, her husband chases the fleeing murderer while Tesla waits for medical help with the victim. Unfortunately, the security chief arrests Tesla's husband as the easiest suspect ,so it's up to Tesla to make them see reason. When reason fails she sets out to find the murderer herself. The really strange thing? Another body has turned up in the waste recycling system but everyone aboard is accounted for. Have there been two murders? And who is this spare man?
Few of the passengers in the the Earth gravity luxury cabins are who their implants say they are. Between her wealth, the tragic end of her career, and her celebrity marriage Tesla is sick of public attention. Luckily the cruise line offers an anonymity option, for a premium, so Tesla plans to enjoy a few weeks without bodyguards. That plan backfires when her husband is framed for murder. Her investigation would be much simpler if most of the people with access to that hallway weren't also enjoying that anonymity and hiding secrets of their own. There is also a highly advanced octopoid robot involved, which Tesla is happy to explain is completely different than an octobot, acting as an assassin. That would make identifying the culprit easier if there weren't a few brilliant roboticists around. Then again maybe the robot has nothing to do with it and its the famous acrobat who's sneaking into cabins. Then there's the body in the waste recycling system. Their best guess is that the body was chopped up and thrown in the trash but how did it get on the ship in the first place? Is it even connected to the murder in the hallway?
In this stand alone story Kowal makes transferring this cruise ship mystery into space appear effortless. The setting and story are so close to something that could happen today on Earth that its comfortable and familiar while only being possible in its futuristic setting. Most of the technology described are things today's humans would absolutely do if they could, although who knows what society will look like in another century. Such as implants that allow people to look up your name and see social media related to you as well as nanobots that create a false identity to be seen by other implants to protect your anonymity. If you have enough money and are worried about your privacy you can get a license for a nanoscreen that shows you as a blur in any video footage or digital images. Need some tools to disassemble the molecular printer in your cabin so you can jury rig it to scan your whiskey for drugs, it can print them.
Overall, The Spare Man is a fun mystery with a 1940's flair set in space. You don't have to be a hardcore sci-fi fan for this one because the tech jargon is minimal. The futuristic details are integral to both the story and setting but somehow feel completely natural. The details relating to Tesla's physical limitations and PTSD triggers are quite realistic although I'm not an expert in service dog training so can't speak to that although I've seen them do amazing things. As a mystery its a good one with plenty of odd twists and turns. As always, Kowal is an excellent writer with good world building and characters who act like real people.
Kowal performs the audio narration herself and Audible listeners gave it 4.8 stars.