After the Arbiter helps Miranda Keyes and Sergeant Johnson to halt the Halo's firing sequence, he swears to protect them from the Covenant as they fight to reach the Ark. However, he finds he is unprepared for the political struggles and moral dilemmas that follow from rejecting the religion and laws he had followed since birth. As he fights to gain ground, he encounters a strange conspiracy involving the Prophet of Truth and the aspiring Hierarch, the Prophet of Justice. Meanwhile, an Unggoy risks his life when he tries to do the right thing and inadvertently ends up becoming a pivotal figure.