Fourth volume of the violent Japanese anime series. Lucy is part of a military genetic experiment, able to dismember victims with invisible arms known as 'vectors'. Lucy loses her memory in the process of her escape from the military compound and takes refuge with two sisters. Renamed Nyu, she still retains traces of her killer nature, shockingly revealed when the government send a team of commandos and another mutant assassin to bring her back. In this final volume, the mysterious organisation sworn to protect humanity must choose whether they can release the deadliest mutant in their arsenal to hunt Lucy down.