"A dark and twisty psychological thriller that straddles the question of what it means to be human." -- Kirkus Reviews Two sisters. One death. No memories. Cora should remember every detail about the night her stepsister, Hannah, fell down a flight of stairs to her death, especially since her Cerepin--a sophisticated brain-computer interface--may have recorded each horrifying moment. But when she awakens after that night, her memories gone, Cora is...