The story is set in the city of Rylan on an isolated island. Everything seems peaceful until a mysterious aura approaches...

Rouge, a skilled swordswoman, has come to visit the city of Lylan. But she's hardly even stepped foot inside when she's suddenly arrested by a band of knights, led by none other than Rita Lylan, the city's governor! One misunderstanding leads to another, and before long, Rouge finds herself defending Rita from a pair of assassins. The struggle ends when Rouge takes a jab from a weird syringe in Rita's place.

When Rouge next wakes, her gender's changed. Rita wastes no time falling in love with her savior, to which her aunt (and the true ruler of Lylan) reacts very favorably. Failed assassination attempts are often followed by another, and having someone like Rouge around to protect her niece might come in handy. That, and given his skill set, he might make a good husband for Rita.

Rouge is initially very much against this idea but soon finds himself agreeing to his new job as a bodyguard. And so begins Rouge's next adventure, both to protect Rita and to undercover the shadows that plague Lylan.