Following this sentence is a whole bunch of spoilers.
Sahra Johnston is the lowest order of slave on a space station, a tunnel rat. She's used to working in the dark and scrounging whatever she can grab in an effort to earn enough credits so that her perpetually-growing family can survive. Scrounging includes the bare-handed capture of a lizard pest known as evriyong.
Her masters are the Tu'att. They are cruel overlords who think they're being magnanimous because hardly anyone eats humans any more. The Tu'att Empire is a network of planets and one starless nexus that the ruling body has essentially forced into a series of Planets of Hats.
Hardly any of this matters to Sahra. Her primary concerns include surviving the day, gaining enough credit to live, and avoiding her bully and older brother Darvan [aka Dangit Duvi].
Sahra finds what she believes to be a Moshikaan slime dog, and then runs into a group of terrorists/freedom-fighters who were looking for their contact - missing, presumed dead. This leads her into an increasing web of intrigue and plots as she tries to make her overlords leace her people alone. Of course, the Tu'att depend on human labor and will not let go so easily.
Her plans of sabotage and 'hauntings' are based loosely on biblical curses.
When Sahra and her friends find an ancient life pod, they branch out to stealing fuel from the enemy. They use adapted pods as 'mosquitoes' to drain fuel in order to fuel more ships.
Sahra is caught on one such mosquito mission and subsequently herded towards a wormhole that used to mean certain death. In fact, the local Humans know it as Death's Gate. Sahra's fate, however, is different to all the others who went through that invisible portal...
...which leads us into Hevun's Ambassador.