In the crime-ridden city of Ergastulum, there exists a group of humans with super strength and speed dubbed "twilights." These twilights define the city with their constant tension with normal humans, and powerful factions of the town—the Corsica Family, the Monroe Family, the Cristiano Family, and the Paulklee Guild—use them as a means to maintain the fragile balance that exists within the city. Enter the charming human Worick Arcangelo and the deaf twilight Nicolas Brown, two long-time friends and business partners of the neutral group "The Handymen." Working as muscle-for-hire, they are willing to take almost any job asked of them in order to make ends meet. One day, they find themselves receiving a seemingly regular job from the police: kill a rival pimp and his prostitute. However, this job is not all that it seems, as it takes the pair down a dangerous path and triggers events that could change the very framework of Ergastulum forever. [Written by MAL Rewrite]