Ten years ago, an inscrutable and abnormal territory known as Hell's Gate appeared in Tokyo and altered the sky and decimated the landscape. The heavenly bodies disappeared, replaced by false stars. At the same time, people who possess various special abilities emerged. Kept secret from the knowledge of the masses, these individuals, known as Contractors, are able to murder in cold blood. Various nations around the world use Contractors as spies and agents, often resulting in violent battles for information. Each fake star has a corresponding contractor, and they vibrate when their contractor's power is being used. As such, contractors are usually identified by their star's Messier Code. However, their abilities are gained at the edge of their humanity. They lack human emotions, especially aversion to killing. Contractors usually work for one of various rival Syndicates as spies and assassins, although the ultimate purpose of the Syndicates is unknown.The story follows a team of two contractors, one doll, and one human on their missions for a mysterious Syndicate. Story lines are generally two episodes long.