This amazing story is an alternative history asking the question "What if Afrikans had conquered and enslaved Europans?" Told mostly from the point of view of the whyte slave Doris Scagglethorpe (renamed Omorenomwara by her first mistress, Panyin Ige Ghika) you're completely immersed in this wholely believable culture. The novel begins with Omo receiving a notice from the Underground Railway telling her that, if she has the courage, her means of escape is at hand. Tattooed with the initials of one owner on one shoulder and her current owner (Kaga Konata Katamba I) on the other, she grasps this chance with both hands.
The book is a brutally honest look at slavery - black humour intended. But since it is fiction, it allows you to look closely at the issues it deals with without the habitual barrier of "it wasn't MY fault so why should I feel bad about it", or "the conditions weren't really THAT terrible", or even "some slaves were treated well". The story is clear; it doesn't matter how you are treated, slavery is slavery, and human nature is to fight for freedom, regardless of the penalties for failure. The novel also shows how arbitrary racism is, by pointing out (through reversal) the idiocy of all the 'proofs' of superiority used by the slavers.
One of those novels everyone should read.