Game of the Universe: Zenith

What happens when aliens invade the earth and force humans to become their slaves inside a game? How does the dynamic of the entire planet change after this? Will giants fall as new ones rise? Arthur is just a normal high-school student, and just one of the 7 billion humans whose life was forced to change within the span of a single night... a night filled with blood and carnage. However, is this truly the end for humankind... or a new beginning?