A girl named Nagisa Akira is said to be the reincarnation of the Virgin Mary (aka Maria's Daughter). The Vatican, realizing this, have sent one of its elite agents, Takagi Chrome, code named “Crimzon” to protect her. Chrome is one of the elite assassins directly under the control of the Vatican who had used to carry out terrorist acts and the assassinations of world leaders. Chrome's new mission is to protect Akira so that she does not fall under the hands of the Protestant English. Thus begins the journey to protect Maria’s Daughter, and the discovery about Chrome’s mysterious demonic power.