Maul has been sent to a prison named Cog Hive Seven by Sidious, in an effort to obtain a nuclear weapon and pass this into the hands of an organisation who will detonate the device within the senate. Though primarily Sidious' plan, Plagueis decides to intervene, not knowing his apprentices true intentions, sending a minion from his banking clan into the prison to monitor progress.
The prison is a constantly changing network of connecting cells and corridors, containing not only the most wretched scum and villainy the galaxy has to offer, but also a variety of deadly alien species, with which Maul and the other prisoners must periodically battle with as part of their stay within the prison. Every inmates heart (in Maul's case, hearts) have been injected with nano explosives, which can be detonated by the prison wardens at any time they see fit. Maul has furthermore been strictly instructed by his Master to avoid detection in the force, thus forcing him to abandon his abilities in the dark side and rely purely on his natural strength and cunning.
Through a series of social and political interactions and relationships, the story creates a complex network of characters interactions, revealing more and more about the prison's inner workings slowly, and I felt that I came to revelations in conjunction with the characters in the story. Like in Schreiber's previous Star Wars story, Red Harvest, the descriptions of the characters are detailed, and the battles vivid and often gruesome, creating gripping suspense during the climatic parts of the story.
In conclusion, if you persevere, you're presented with a well told, brutal and intriguing tale of Maul's past, whilst learning enough of the expanded Star Wars universe to keep things interesting in the canon of Star Wars novels. Recommended for fans of Star Wars and Darth Maul/Plagueis in particular.