When an asteroid threatening to wipe out planet Earth appeared, humanity's brightest minds came together to develop the "Moon Shield" plan. To protect the planet, rockets would blast the asteroid apart, and the Moon would shield the Earth from the remaining debris. However, the plan failed by the smallest of margins: one sliver made it past the shield and crashed into Earth. There to witness the end of the world was Moon Yoo, a researcher left stranded on the Moon. Unable to find the courage to end his life, Moon decides to make the most of what he has as the last man alive. With supplies to last a lifetime and all the time in the world, Moon decides to explore the vast lunar base, unaware of the many secrets that lie in wait to be discovered—and the fact that he may not be as alone as he initially thought.