Leo and Polina are twins. One day, during a mountain excursion with their mother, a geologist, they experience a dramatic and tragic accident: the twins, helpless and terrified, watch as their mother is knocked down and carried away by a rockslide. The mother falls into a coma, and the twins react in diametrically opposite ways to the psychological trauma of the event. Polina has forgotten everything – her long and short term memory is suddenly erased. Leo, on the other hand, realises that he now remembers absolutely everything. Even the smallest events of the past are now stored in what feels more akin to a computer hard disk than a human memory. This observation gives him an idea: every evening Leo writes to his sister, recounting stories from their childhood, memories of holidays – the big events and all of the little ones too that weave together making us who we are. Time passes, and their mother hasn’t stirred from her coma, so the children seek to take matters into their own hands. Remembering that the doctors said she might be able to hear them, they try to stimulate her mind by talking to her about the science that she is so passionate about, in the hopes that it will wake her.
As with the other books in this collection, the author has based his story on interviews with scientists – in this case specialists in the fields of geology, population genetics, physics, storytelling, neurology and neuropsychology.