An impoverished life inside a dangerous, walled-in city surrounded by a hostile wasteland didn't give Rain much to live for, but when he makes a sacrifice made for a childhood friend, Rain unwittingly finds it leads to the opportunity to become an agent of the high-tech secret society known as the Vincent. Before his training is even complete, Rain finds himself in over his head with danger at every turn. Armed with nothing but long-term amnesia, a clever mind and wry sense of humor, Rain must do everything in his power to prove he has what it takes to become a Vincent agent-all while simultaneously outmaneuvering a malicious spy.