Koihime+Musou is based on an eroge game by Baseson, which was loosely based on the classic Chinese novel Romance of the Three Kingdoms.
Plot
Having lost her family to bandits during night raid, Kanu swears, she will not let others share the same pain. She quickly becomes a well-known and feared by villains bandit hunter. During her journey she comes across others, who wish to join her cause. One of them is a girl RinRin, who had similar experience with bandits in the past.
External Links
Official
Other Sources
Other Wikis
References