[EN]
On October 1, 2173, at 10:00 a.m., an unidentified giant object appeared in the sky over Edogawa Ward, Tokyo, and remained there for four hours before suddenly disappearing. After that event, unidentified creatures, which are a fusion of machines and living things, began to appear all over the world.

[JP]
2173年10月1日午前10時00分,東京都江戸川区上空に正体不明の巨大物体が出現。4 時間上空に留まり突如消失。その出来事を機に世界各地で機械と生物が融合した正体不明生物が出現し始めた。