A heart of Halo is Spartan 117, the Master Chief. In the next chapter of the Chief's story, you'll face his greatest challenge yet, but they're not alone in the fight. The main batteries are shut down. We're stuck out here. You have one bullet against an entire army. What can you do on your own? I told you. It's enough. So I see. I need you to understand. There's not much time left. If you knew how we were going to die, I wonder how you were going to die. How would you live your life? How would you live your life differently? What happened? Where is Cortana? The rogue AI known as Cortana is gone. She's been deleted. How? By you? Of course not. Did you hit your head or something? Don't you remember? My instructions were to enter this installation, imitate Cortana, and lock her down for retrieval. Yours were to take her back to the infinity for deletion. So if it wasn't you... Okay then. There's something else. On successful deployment, my deletion routine was supposed to complete. Still here? Good. Good. Something stopped your deletion. We need to find out why. But this wasn't the mission. The missions changed. They always do. Are you sure? Thanks for watching.