If you were one of the many wondering why Spartan Jameson Locke is hunting down Master Chief John 117, Microsoft has something special for you this morning. Today the company unveiled the Halo 5: Guardians Launch Gameplay Trailer on Xbox Wire.

The Launch Gameplay Trailer — trust me, that’s the last time you’ll read its entire name here — opens with Dr. Catherine Halsey discussing the UNSC’s plans to kill her because of recent actions she’s taken. Halsey is the architect of the Spartan program of which John 117 belongs to.

Promotional materials for Halo 5 indicate that John has gone rogue. In this trailer we see him disobey a direct order to return to the UNSC Infinity in a Pelican dropship. We also see Fireteam Osiris gearing up to take down John and the Blue Team by any means necessary. The game’s campaign involves players becoming both Master Chief and Spartan Locke. The entire campaign features co-op, with players taking over members of John and Locke’s teams seamlessly. There’s a massive multiplayer experience called Warzone and a more traditional Arena multiplayer coming too. Unfortunately, 343 Industries, the game’s developer, confirmed last week that the Forge creation engine won’t arrive until this coming December.

Halo 5: Guardians launches officially on the Xbox One October 27th.