Ten years ago, a mysterious spatial anomaly now known as Heavens Gate appeared in South America, shortly followed by the opening of Hells Gate in Tokyo altering the sky and wreaking havoc on the landscape. The real stars disappeared, replaced by false stars. During this time, people possessing various special abilities — called Contractors — emerged, each capable of different supernatural feats. Following the disastrous Heavens War, the United States lost its dominant position as a superpower to a mysterious organization named the Syndicate. The story revolves around a Chinese contractor codenamed Hei as he undertakes various espionage and assassination missions in Tokyo.