This book takes place in an alternate history, set in the UK. There are three twin boys in what appears to be some kind of orphanage, they are being cared for by three women that are taking shifts and are called Mother. For instance the woman that wakes them at starts the day is Mother Morning, she notes each of their dreams down in a large book.
Each child is given medication every day, and are told that it is to help with a bug that they have contracted. It turns out though that they are clones of a serial killer, and the drugs in fact are going through medical trials with the notes taken on their affects on the children being used for the research.
I thought it was very well written, and the drip feed of new information throughout the book was paced just right.