deluded Covenant from killing all sentient life a second time. Though he promises an alliance, Gravemind has ulterior motives. His Flood infest the human ship In Amber Clad and makes a slipspace jump into High Charity itself, in an effort to use the station to escape the confines of Halo. Having taken over the city, Gravemind questions the A.I. Cortana, who was left behind to destroy High Charity if Halo was activated. Gravemind says that he has questions that he will ask, and Cortana agrees to answer them. A short story in the 2009 Halo: Evolutions anthology details the conversations that follow. Gravemind is one of the primary antagonists of Halo 3. While the Master Chief and Arbiter have returned to Earth in order to stop the Prophet of Truth, the religious leader of the Covenant, from activating a Forerunners artifact buried in Africa, Gravemind turns High Charity into a Flood hive and sends an infected cruiser to Earth in an attempt to infest the planet; this plan fails, and a message from Cortana informs the Master Chief and allies of the existence of the Ark, a special installation built by the Forerunners outside of the Milky Way galaxy where all the Halos can be fired remotely. Seeking to stop the rings from firing by Truth, Gravemind manipulates Arbiter and Chief as allies, so the Flood once again ally with the Chief and Arbiter. As soon as Truth is killed, however, the Gravemind then turns on both Chief and Arbiter, where the pair escapes the Flood's clutches and Chief rescues Cortana from High Charity. Despite being tortured by Gravemind, Cortana has managed to keep a secret safe from the Flood; she has the activation index of Installation 04, which she captured from 343 Guilty Spark during Halo: Combat Evolved. Using the index, Cortana can activate the local ringworld, destroying Gravemind and the Flood, but sparing the galaxy's sentient life. Gravemind finally gains this knowledge, but too late; the Master Chief escapes with Cortana, destroying High Charity in the process. Gravemind survives the blast and attempts to rebuild himself on the new ring. Despite his best efforts, the Master Chief and company activate Halo, destroying it and finally defeating the Flood. Resigned to his defeat, Gravemind nonetheless insists that it will only slow – not stop – the Flood. Other appearances of the Gravemind is in Halo Wars and the Halo