From Halopedia, the Halo wiki
The Halo 5: Guardians Spartan Locke Ad, also called All Hail, is a video advertisement which is part of the Hunt the Truth marketing campaign for Halo 5: Guardians. Released on March 29th 2015, it depicts Spartan Locke confronting the Master Chief on a ruined planet. It was aired along with the Master Chief Ad, which features similar circumstances with the characters' roles swapped. Both trailers were directed by Rupert Sanders, who previously worked on the Believe campaign and the We Are ODST live-action trailer.
This trailer marks the first appearance of the official release date of Halo 5: Guardians; October 27, 2015.
This trailer, along with The Cost, was taken down by Xbox on its YouTube channel on April 22, 2016.
Jameson Locke stalks through the bombed out ruins of a building. He emerges into the open air in the midst of a large debris field on an unknown Human colony world. Severely damaged skyscrapers still stand in the distance.
He turns toward a pitted and scarred stone statue of Spartan 117 and begins walking toward it. A damaged UNSC Infinity can be seen floating in the sky.
Locke outstretches his arms to gesture to the devastation surrounding him.
As he speaks, the point of view briefly switches to Locke's as he looks through his helmet's faceplate.
As Locke says "you" for the first time, he gazes upward at the statue, representing the idealized image of John-117 as the hero and savior of humanity, with the quote "Duty and Honor Above All" below. He then looks down to the figure below the statue; the real Master Chief, lying in the dirt appearing badly injured, armor still sporting a smoldering hole in the chestplate. Locke drops his rifle, and releases the magnetic locks holding his pistol to his armor, which flies into his hand. He points it at the Chief's head.
Locke is holding an M395 DMR in the trailer, but his HUD shows he has a BR85HB battle rifle.