Liu Zhenyu (Hyun Bin), the head of an investment company, went to the ancient Spanish city of Granada and accidentally experienced an AR game with the theme of urban history. Due to investment needs, he met the game designer's sister Zheng Xizhu (Park Shin Hye). What Liu Zhenyu did not expect was that in the process of experiencing the game, the real world and the game world were closely entangled. His former friends died strangely in the game battle, and even turned into NPCs in the game, repeatedly appearing as enemies/allies, forcing Liu Zhenyu to be in a state of eternal battle, physically and mentally exhausted. In a sense, Liu Zhenyu is broadcasting the game live to TV viewers around the world, and we have become "cloud players", fighting monsters and upgrading through Hyun Bin's perspective, while guessing the game tasks and game rules of the next level.