The game takes place in an alternate history version of Japan in 1929 dealing with the repercussions of a fallen meteorite named the "Black Garnet".[4] The meteorite starts the spread of a disease called "Chimera", which causes people to turn into dangerous and destructive creatures, leading to the death of 3% of the world's population and the infection of many more.[4] The player takes control of the character of Asahi, a member of the "Special Force Valkyrie" ordered to eradicate the Chimera-infected people to stop the spread of the virus. Source: Wikipedia, "[en.wikipedia.org/wiki/Dark_Rose_Valkyrie Dark Rose Valkyrie]", available under the CC-BY-SA License.