Birth of first large batch of girls born from Lucy's infection, including Nana and Number 28. Many of these girls kill their families upon reaching their third birthday. As the Institute begins to overflow with the Diclonius infants, Chief Kakuzawa orders any further such children to be euthanized. Kurama, not wishing to leave this grim task to another, performs them himself.
Mariko is born to Hiromi and Kurama. After promising the dying Hiromi that he will keep their daughter alive, Kurama makes a deal with Chief Kakuzawa for this purpose, but Kurama is kept away. Mariko is locked in a specialized vault due to her powerful vectors. Her only known human contact is through Saito, who proclaims herself to be the little girl's foster mother. The births of Diclonius twins to Number 3's mother confirms that parents are the source of this mutation, and leads Kurama and the younger Kakuzawa to conclude that an original infecting party may exist. (There is a disputed account stating that one of these twins was Nana)
Young Lucy is befriended by Aiko Takada. The pair are soon accused of murdering Aiko's abusive father and Aiko is killed by Kurama while attempting to apprehend the Diclonius 'Queen' that he and Kakuzawa have recently realized existed. Kaede (called Lucy by the Institute) surrenders in a vain effort to save Aiko's life. A deep and abiding hatred arises between Lucy and Kurama as a result of this. Kurama, anxious over not being able to see Mariko, begins a parental relationship with Diclonius Silpelit, Number Seven. Nana believes Kurama to be her real father.
According to an account given by Chief Kakuzawa, Lucy's mother is found while searching for her and held by Kakuzawa, forced by rape to bear another Diclonius child, the only known male. After this birth, she commits suicide, and further efforts to use her body for this project, called 'Lebensborn' after a Nazi experiment, prove futile.
In high school, Yuka befriends and becomes senpai to the nervous and reserved Nozomi
Kouta and Yuka prepare to enter University; Upon learning that Kouta, who failed to achieve entry to higher-ranked colleges, will be attending Kamakura's so-called 'safety school', Yuka begs off her own entries to better schools, in order to be near him; Professor Kakuzawa begins to formulate plans for Lucy's eventual escape. Mayu's mother remarries.