Seventeen-year-old Mariko is the only daughter of a prominent samurai, which means her only future was marriage. However, on her way to the imperial palace to meet her betrothed for the first time, Mariko's caravan is attacked by the Black Clan, who were hired to kill her. Escaping and disguising herself as a boy, Mariko infiltrates the Black Clan with the intention of getting revenge--instead, she may fall in love with the Clan's leader.