Year 2100, the world has been overrun by the undead. The living who became the first witnesses have been added to their ever growing numbers. Only a small amount of survivors, with their limited supplies in tow. Established a last base in a military base boot camp. A tired old man named Zairo and his small group are what's left of humanity. In the brink of defeat all his crew were overrun by the sheer numbers, but one of his close friends had made a prototype time traveling device that could send anyone back in time. However, it could only be used on one person. Before turning Zairo flipped the time devices switch. In a flash a bright light had blinded Zairo, unbeknownst if the device worked as intended. Losing Consciousness his vision goes black. When he awoke he found that he is young again in his twenties . Moreover, it is also a few months time before the outbreak begins. With the limited time Zairo has, he prepares for the end of the world. Operation Undead Defender begins.