Five complete strangers are brought together through the guise of one unknown man. They have been summoned for a project – a project of which success would guarantee them riches and a life beyond their wildest dreams. They’ve been given no information, no data, no identity. The project is dubbed X. The five men jump on board. Finally, the fateful day arrives. Ryu, Roh, Jeong, and Kyu gather at the bank wherethe plan is to be carried out. Under Hwan’s leadership, the process is executed smoothly, until a minor slip up grinds the plan to an unexpected halt. Police swarm to the scene of the crime and the men barely manage an escape by taking one of the captured people hostages. They quickly run to the place where they are to meet Hwan. When they arrive, however, they discover Hwan’s body – dead. Slowly, they begin to realize something is going wrong. In light of the shocking circumstances, suspicion falls on each other, as the men stealthily attempt to find who X is. Who is this X? What exactly does he want? Why did he bring these men together? Who is the architect behind this grand, master plan?