The Diclonius (two-horned human) are mutants created by humans. It has a special ability that can be described as a sixth sense. These mutants have enough power to exterminate the whole human race. Afraid of their powers, people isolate them in research labs to be studied. One Diclonius girl, Lucy, breaks out of confinement, kills her guards and escapes. She falls into the ocean after being shot and ends up on a beach. There, she meets Kuota and Yuka. They name her Nyuu and begin to live with her.
The story goes on until more Diclonius are sent to find Lucy/Nyuu but to their shock they kept on finding the innocent Nyuu instead of the blood thirsty Lucy. These Diclonius found the warmth of friendship and love of a caring family through Kuota and Yuka's guidance to innocent Diclonius like Nana and Nyuu/Lucy. And the turn of events reveals a shocking past between Kuota's forgotten childhood memory and Lucy's painful secret.
The essence of this anime/manga, stands about how normal humans (like us) dangerously hunger for more than what science has given us even if it costs us our future. Inventing the Diclonius thinking that it would make us more powerful to the point that we even wished to be God himself. And the anime also shows to us how the warmth of caring and friendship can save a lost soul seeking acceptance and love.
The ending was full of tear-jerking episodes, especially on the part when Lucy herself trying to kill the evil DNA inside of her (the one who actually pushed Lucy into killing humans to make a WORLD for HER kind.) and saving Kuota using all her powers...
This anime should be watched over and over again!!!!