member and tasked to kill each other as a means to eliminate the weaker half. Darrow is forced to murder Cassius' brother Julian to survive, but Cassius can only guess who may have killed him. Each House is assigned a fortress and a scepter, called a standard, to defend within the Institute's confines, with the goal of warring with each other until one House enslaves all others with the standard. Mars fractures into factions: one led jointly by Darrow and Cassius, one by Antonia, one by Titus au Ladros, and the antisocial Sevro going off on his own. To neutralize the violent Titus, who has been raping the female slaves left in Mars' fortress, Darrow manipulates House Minerva, led by the young woman he met briefly upon his arrival at the Institute and whom he has dubbed "Mustang". Mustang and her troops take the Mars fortress and imprison Titus. Sevro helps Darrow escape and capture Minerva's standard, which he trades to reclaim Mars' castle. Darrow takes over as the Primus (leader) of Mars, and Sevro and his group of "Howlers" declare their loyalty to him. Darrow realizes from the captive Titus' manner of speech that he is a fellow Red impersonating a Gold. To maintain his cover, Darrow allows Titus to be executed. Darrow captures Minerva's fortress and defeats their strongman Pax au Telemanus. Mustang reveals the existence of "the Jackal", the leader of House Pluto who is terrorizing other Houses. Antonia and some of Titus' former followers attempt to overthrow Darrow, but he manages to thwart their plan. Lilath, a messenger from the Jackal, secretly reveals to Cassius that Darrow killed Julian. Cassius challenges Darrow to a duel outside Mars' fortress, wounding him and leaving him to die. Darrow is rescued and nursed back to health by Mustang. They begin to develop romantic feelings for each other as they flee to avoid discovery by Cassius, now Primus of House Mars. Conquered students are systematically "enslaved" by other Houses, forced by their honor to serve their conquerors. Darrow and Mustang begin to amass an army by recruiting many Oathbreakers, the wandering slaves who have chosen to disobey orders, with Minerva's standard. Darrow prefers that his captured foes swear their allegiance and join him, rather than serve him. Learning from his previous mistakes, he frees these slaves and takes responsibility for their actions to gain their allegiance. He gains the loyalty