Who were imoge ne and alafair?

Imogene and Alafair are characters from the novel "The Little Friend" by Donna Tartt. Imogene is the older sister of the protagonist, Harriett, while Alafair is the mysterious figure whose death becomes the focal point of Harriett's quest for truth. The novel explores themes of childhood, grief, and the complexities of familial relationships through the lens of their interactions and the impact of Alafair's life and death on the family.