Lost Days 0: Queen's Dream is a Sci-Fi visual novel for the Sega Saturn about Io, a pilot/spy who was sent to United Europe to investigate Cornelli, meanwhile, the arrival of a skilled assassin threatens her mission.

Lost Days 0: Queen's Dream is a Sci-Fi visual novel for the Sega Saturn about Io, a pilot/spy who was sent to United Europe to investigate Cornelli, meanwhile, the arrival of a skilled assassin threatens her mission.

Seventeen years have passed, yet the shadow of the Great War still hangs upon the world. On February 28, 2019, the 3th World War began. The war was between China and the United States of America. A series of sanctions imposed by the United States ignited this war. A feature of the Great War was the use of robots, manned bipedal machines, the Metal Knights. China, now called Great China, became a union of republics, consolidating itself as the largest economy.

After that, Great China established a system to remain militarily stately. The Great Generals system. Each of the Great Generals acts as a strong independent force. They are stationed throughout the nation. Zhaoky base with Houke and Rinshu, Weisho base with Ren and Goke, Yannro base with Gakuk and Gekishin, Quinou base with Koshou and Lu, and Chukou base with Kyou.

You are Io of Yannro, Vice General, commander in the Gekishin Army and a military spy. Originally you was a rebel leader infamous for organizing resistance acts in United Europe.