In the face of a pandemic, an unprepared world scrambles to escape the mysterious disease causing sensory damage, nerve loss, and, in most cases, death. Neffy, a disgraced and desperately indebted twenty-seven-year-old marine biologist, registers for an experimental vaccine trial in London--perhaps humanity's last hope for a cure. Though isolated from the chaos outside, she and the other volunteers--Rachel, Leon, Yahiko, and Piper--cannot hide from the mistakes that led them there. As London descends into chaos outside the hospital windows, Neffy befriends Leon, who before the pandemic had been working on a controversial technology that allows users to revisit their memories. She withdraws into projections of her past--a childhood bisected by divorce, a recent love affair, her obsessive research with octopuses and the one mistake that ended her career. The lines between past, present, and future begin to blur, and Neffy is left with defining questions: Who can she trust? Why can't she forgive herself? How should she live, if she survives?