Original sentence: In 1884 they also discover, by a process of deduction, that they are in fact not cousins but brother and sister.This makes Lucette the uterine half-sister of both of them.Van and Ada fall passionately in love, and their affair is marked by a powerful sense of romantic eroticism.Van's father, Demon, is in fact father to them both, and Ada's mother, Marina, is mother to them both.Van's supposed mother, Aqua, is Marina's sister, and Ada's supposed father, Dan, is Demon's first cousin
Edited sentence: Although Ada's mother keeps a wedding photo dated August 1871, eleven months before her birth, they find in a box in the attic a newspaper announcement dating the wedding to December 1871; and furthermore that Dan had been abroad since that spring, as proved by his extensive filmreels.Furthermore they find an annotated flower album kept by Marina in 1969-70 which indicate, very obliquely, that she was pregnant and confined to a sanatorium at the same time as Aqua; that 99 orchids were delivered to Marina, from Demon, on Van's birthday; and that Aqua had a miscarriage in a skiing accident.Hence he is not Ada's father.In 1884 Van and Ada fall passionately in love, and their affair is marked by a powerful sense of romantic eroticism.It later transpires that Marina gave the child to her sister to replace the one she had lost--so she is in fact Van's mother--and that her affair with Demon continued until Ada's conception.The book opens with their discovery that they are in fact not cousins but brother and sister.The passage is notoriously difficult, more so as neither of them explicitly states the conclusion they have drawn (treating it as obvious), and it is only referred to in passing later in the text.This makes Lucette (Dan and Marina's child) the uterine half-sister of both of them