The trailer was narrated by Ikora, who speaks to the player's Guardian in secret to reveal that an "ancient gate" has opened on Mercury. "Past and future" machines are pouring through it with the intention of remaking "the universe in their image." Ikora describes how Osiris anticipated this but was banished because of his dangerous ideas. She also says it's unclear if he'll serve as an ally or bring further destruction.
As you'd expect with talk of machines, the Vex appear to be the primary enemy in this expansion. Further specifics were not shared, but we do know Mercury is coming as a new planet. Curse of Osiris's release date is set for December 5.
Destiny 2 recently launched on PC, but this expansion is headed to that platform in addition to PS4 and Xbox One.
Source: GameSpot
