Lost Memories ( 失われた記憶 / うしなわれたきおく / ushinawareta kioku ) is the ninth chapter of the Elfen Lied manga series.
Despite Kurama's insistence at its necessity, Bando loudly demands to know why he must undergo the castration procedure. He also asks fitfully about who Lucy is, and how she wields such potential. Kurama begins to explain the Diclonius threat, in which the Diclonii will eventually end up overthrowing the Human race. He also talks about how Lucy was a prime example of the first new Human-level mitochondria, and the first dramatic evolution of the species in two-hundred-thousand years, and how Bando himself may play a role in Humanity's extinction unless he accepts the operation. Bando doesn't like any of the facts but listens on docilely.
Over the image of the blissfully unaware and sleeping Nyu, Kurama's words about the apocalyptic nature of the Diclonius threat have come to fruition. Next to her at the Maple House, Kouta rises from a less than restful sleep, fearing that he might have caught a cold. Still thrown off by Yuka's tearful exit, he tries to remember the time eight years ago when he and his family visited and realized that it was the same year his father died in an accident while his sister, Kanae, passed away from an illness. Perhaps a little too quickly, he dismisses the idea that this is part of his memory loss. He quickly gains two other problems, one of them is that he has a cold, and another is that the now awake Nyu is naked from the waist down, innocently oblivious to the distraction she's causing him. As his fever starts to rise, he asks a distraught Nyu for some water, but quickly realizes his request for water is going no better than his request that she put on some pants. However, both of those facts fly over her head. For his sake, she struggles a little bit but manages to almost say the word 'water,' her very first real word since 'Nyu.' Unfortunately, she brings him a slipper instead of a much-needed glass of water, for which he thanks her nonetheless.
Outside, a relaxed, but nervous Yuka waits outside the door before entering and announces that she has brought clothes for Nyu. She also firmly states that she isn't there for Kouta, only to be assaulted by Nyu's pleas for water. While applying some wet towels to his forehead, she spots a pile of small items that Nyu fetched, none of which were water, and wonders if some ritual was in play. Kouta's attempt to apologize is at first mistaken for being about his getting sick, but Yuka quickly realizes it was about his failure to remember what she asked about the previous day. While Nyu almost blinds herself with a lamp, Yuka gently tries to brush off the apology, saying she won't forgive him until he remembers anyway. Kouta asserts that the reason he can't remember must have been due to the shocks and grief he suffered that year, recounting the manner of his father and his sister's deaths.
As Nyu drops and breaks a lamp, Yuka immediately realizes that what he said is at odds with how his father and sister died. Horrific images (likely taken from police reports, since she was not there) erupt in her mind of Kanae being torn in two while hoisted in the air. Her uncle--their father--became enraged and rushed a shadowed figure who seems to be responsible and then decapitated. All this while Kouta watched in tears, covered in their blood, with his father's head at his feet while cradling his little sister's upper torso, all described as having happened on the train ride home from visiting Yuka's family. Yuka painfully realizes that his seeming air of meanness, insensitivity, and denseness is, in fact, the result of traumatic amnesia, a defense mechanism against living with those horrific memories.
When Kouta asks her to repeat what she said (regarding the manner of his father's death, supposedly an accident), Yuka claims that she didn't say anything at all. A brief memory of her younger self, exhorting him never to forget her makes her cry, to realize he had no choice but to forget all he knew of that part of his life. As she starts to cry again, he sleeps off his fever while Nyu watches quietly.
- The cover features Nyu dressed in more or less regular clothes, perhaps some of the things Yuka picked up for her, though her headwear needs adjustment if she plans to go out in public.
- A gag very similar to Nyu's comical efforts to obtain water for Kouta occurs in the Nickelodeon animated series Avatar: The Last Airbender involving the ill Sokka, Katara, and their ill-informed helper, the winged lemur Momo. TVTropes refers to this gag as Rummage Fail.