Another world: Lexia, the first princess of the Kingdom of Arcelia. When it comes to decisiveness and the ability to take action, no one can match her; in some ways, she is the "strongest" princess. As a result of being extremely bored with life in the royal castle, the words she uttered were... "I've made up my mind! I'm going to set out on a journey to save people who are in trouble!" So, forcibly bringing along Luna—a girl who is her bodyguard and has a background as a top-notch assassin—Lexia sets off on an adventure around the world.