In the kingdom of Alderia, First Princess Leone defies the norms by rejecting dresses for iron armor and serving her country as a knight general. Nicknamed the "Golden Lion," she is feared for her bold courage in battle. However, in the midst of a military conflict, Leone unexpectedly receives a proposal of marriage from Zergios, her enemy nation on the brink of collapse. Surprisingly, it comes from none other than Marshal Berthold, someone with whom she has clashed swords many times in the past. A man of few words and a brusque demeanor, Berthold's conversations with Leone mirror the exchanges between two seasoned military figures. Gradually, however, his straightforward approach begins to break down Leone's barriers. Where will this marriage take these two people whose lives have revolved around nothing but the sword?