The future: The ability to map the human cortex neurone by neurone has been perfected by way of scanning. While people live, it is now possible to place a copy of a person's personality into data storage. A Similarity. The main reason is so the bereaved can communicate with them after death. Geolog is a world leader in this technology. For two middle-aged sisters, Mia and Emma, living on an isolated farm on the periphery of Hastings, this technology divides them. When Mia's husband is murdered in Hong Kong and she uses his Similarity online, a family secret is revealed forcing them to ask some profound questions about life and the continuance of the human soul. And all the time, Geolog, the technology giant, is monitoring them.