While no gameplay was shown off, a short cinematic trailer of Halo Wars 2 set the tone for where the new game will be taking the crew of the UNSC Spirit of Fire. As most trailers start off these days, a wounded Marine was being dragged by his fellow Marine, firing his pistol at an unknown threat. Eventually, he runs out of ammo and goes limp, at which point the trailer showed off brief glimpses of the Spartans assigned to the Spirit of Fire being assaulted by some unknown enemy. Unlike how Spartans in the Halo universe typically perform though, they are being thrown around, restrained, and hardly winning their fight.
The end of the trailer concludes with a shot of a new Brute antagonist, who chuckles and says, “Yes. Run, little Demons.” Of course this is no regular Chieftan, and this is indicated by what appears to be his new personal weapon, a glowing red club or hammer (in typical Brute fashion).
Halo Wars 2 is a continuation of the story in the first Halo Wars, where the UNSC Spirit of Fire discovered a Forerunner Shield World filled with Forerunner ships. To deny the Covenant access to the ships, the crew decided to sacrifice their FTL engine, though this meant that the ship would have to travel at normal speeds to reach any destination. This means that the crew would have to wait years, decades, or longer until they can be rescued, so many of them went into cryogenic sleep to pass the time. It was assumed by the UNSC that the ship was missing in action and eventually lost with all hands, even up to the time of Halo 4.