The premise of the book is rooted in the brutality of the Atlantic slave trade, viewed through a surprisingly optimistic lens. Where the slave trade caused irreparable harm, new opportunities for community and identity have been born. The wajinru, a mermaid-like race living in the sea, are the sea-born offspring of pregnant black slaves who have been tossed over the side of slave ships to die. The wajinru live with the opportunity to live a life grounded not in their past, but rather in the present: each of the wajinru is possessed of a memory that blanks out the pain of the past. Yetu, however, is the exception to this. She is the wajinru’s Historian, who holds all the generational memories that are too painful for her culture as a whole to hold. They overwhelm her, subsume her, until she simply can’t take it any longer. The past begins to blur with the present, and the imbalance between the two is too much for anyone to handle.