Now, some of this has been echoed by many different members of this forum, but I have not once heard someone put down this particular theory. I believe that when the Arbiter said “You have to do more than walk in his footsteps.” Particularly, I cling to “…walk in his footsteps.” ‘His’ referring to Master Chief Petty Officer of the Navy Spartan John-117, who we know to have gone missing within 72 hours after joining the Infinity’s crew post-Halo 4. So my theory is that over the course of Halo 5, Agent Locke who we know is looking for the Master Chief, will be following in his literal footsteps in an attempt to find him. He will visit the remains of Installation 04, what remains of Old/New Mombasa and Voi post-glassing, Installation 05, and the Lesser Ark Installation 00, all in an attempt to find clues as to the Master Chiefs current whereabouts.
Now, you may be asking, why go to all those places where he has already been in the far past, rather than recent places? Because “The seeds of our future, are sown in his(Master Chief’s) past.” What happened to the Chief at these places that could not be witnessed in a simple video? What has he gone through? Why did he leave? Where did it all begin? And where is he going?
Now, honestly, perhaps Agent Locke is just viewing these all as videos, or stories. Perhaps this what the new H2A terminals show rather than what happens in-game. Who knows. However, what led me to believe that Agent Locke will be visiting past Halo locations in person, is the promotional artwork for Halo: Nightfall, which is set to be his origin story. It shows what is most likely the remnants of the first Installation 04. This could mean one of two things: It will be featured in Halo: Nightfall, or it is foreshadowing a Halo 5 location. Granted, there probably wouldn’t be much to see at Installation 04 at this point. The surface is probably burnt up, significant locations destroyed, etc. If I’m not mistaken, Installation 05 is pretty much nothing, but glass post-Halo 2.
But in the end, the whole purpose of revisiting these locations is to track down the Chief by following his steps every step of the way through his journey. A journey, that will likely lead him back to Installation 00, which is still intact, but experiencing inclement weather due to Installation 04B’s premature firing directly above it and subsequent destruction. I believe that to be the setting of the original Halo Xbox One teaser trailer, and a still from said teaser is shown again during the Master Chief Collection trailer. Chances are. Agent Locke will track Chief here, and that is where their two stories will intersect in Halo 5.
Only time will tell what, if anything about this theory, holds up in even the smallest regard. What do you guys think about it?
Edit: Forgot to mention, the reason they’re looking for him is due to the impending return of the Flood. The primary basis for the Flood returning in Halo 5 is the Flood tease in the latest Halo: Escalation issue, as well as the original concept artwork of what is likely Sangheilios, which had what appeared to be Flood dispersal pods flying through the sky. Chief is one of the few who made it back from Installation 05 alive and has the most experience in fighting the Flood, thus, he is an invaluable asset when it comes to training the latest generation of Spartans to effectively fight the Flood.