The greenhouse effect is out of control in the near future, causing Earth's environment to fall apart. People are forced to live in underground settlements to survive, with scientists working for mankind to return to the surface again.

After completing his training, an elite young assassin embarks on his first mission and is quickly ensnared in an intricate plot laid by powerful people pulling strings from the shadows. Upon failing to complete the assignment, he is forced to go on the run—from the government and rival assassin groups alike—as he seeks to unmask the players behind the conspiracy.