An unknown girl with invisible hands, or vectors, and telepathic powers escapes from a secret facility. The next day two cousins, Kouta and Yuka, find her. But she is different from before. She can only say one word, nyuu. Not knowing anything about her, the two cousins take her in. Kurama, the head scientist from th efacility where she escaped, has sent a merciless man, Bando, after her.

After alerting the soldiers and Kurama to Lucy’s whereabouts, Nana confronts her and the two begin to fight in a cemetery. Can Nana hold Lucy off long enough for Kurama and the others to arrive? Meanwhile, hearing loud noises in the cemetery, Mayu stumbles upon the two fighting.

Bando escapes from the hospital, still trying to find Lucy to satisfy his grudge against her. Professor Kakuzawa Yū's decapitated body is found by his assistant and Kohta. While searching for Lucy, Kohta and Yuka develop a fondness for each other as displayed through a kiss. Finally, Lucy is found by Kohta and Yuka and taken back home.

More of Lucy's past is revealed: Her meeting with Kouta, their friendship that will end in tragedy, and the reason why Lucy became the killer she is today.

Yuka informs Mayu of Kouta's past. Meanwhile, Lucy and Mariko find each other and face off in a fight. Now, Nana and Kurama have to find Mariko because Kurama needs to kill her...