I like both science fiction and mysteries, so I'm always happy to find a good SF mystery. It takes place in a cylindrical artificial habitat called One One One which has been created by an artificial intelligence. A party of humans has been allowed in to study a sentient race the AI created called the Brachiators. They live at the very top of the cylinder, clutching the foliage for dear life and eating the fruit that grows there. The human party's living conditions are equally precarious, a series of hammocks and ropes hainging from the ceiling of the cylinder. A fall means certain death, both from the distance of the fall and because the lower levels of the cylinder contain other environments which are poisonous to human and Brachiator life.
Our protagonist, Andrea Cort, is an investigator for the Diplomatic Corps Judge Advocate. She is sent to One One One to investigate the deaths of two humans. It appears that they may have been killed by the AI, but it would be diplomatically disastrous to accuse the AI, so she has been ordered to find someone else to accuse. Andrea, following in the long tradition of dark horse investigators throughout the mystery genre, is more interested in finding out what really happened than in finding someone to pin it on. She has quite an adventure along the way.
I don't know why, but I often like books with damaged protagonists. They tend to be more interesting to me than happy, well-adjusted people. Andrea Cort has a dark event in her past that ruined her life, and she carries around a lot of anger and hatred, both for herself and for her situation. That anger helps drive her and keep her alive, even as the killer is now gunning for her.
I gulped down Emissaries from the Dead in one sitting. It kept me interested, and I wanted to know what happened next. This is why I read SF--for the books that grab you and won't let go until you find out what happens. Such reading experiences are increasingly rare for me. Highly recommended.