UPDATE 31/10/17 4.00pm: Bungie has revealed a little more detail on Destiny 2: Curse of Osiris, such as the fact it will host an increased level cap.
Players will be able to level up to 25 and boost their Power Level from the current max of 300 up to 330 (with legendary mods presumably still able to push you five levels beyond that).
The Curse of Osiris will introduce Sagira (voiced by Firefly and Homeland's Morena Baccarin), a new female Ghost which belonged to Osiris before she became separated from him. Destiny: House of Wolves character Brother Vance, who previously organised the Trials of Osiris tournament, will also return as part of the story.
Vance and Vanguard warlock leader Ikora, once Osiris' pupil, will help guide you through the Infinite Forest - "a simulated reality in the middle of time, controlled by the Vex" - Mercury's new patrol zone.
The expansion will reveal new information on the Vex, with details on what they've been doing through time and space throughout Destiny up til now. Does it have something to do with milk?
As previously announced, the DLC will add "a new quest, new missions, new strikes, new adventures, and the new raid activity". Does that mean a whole new raid? "A new raid activity," Bungie repeated.
ORIGINAL STORY 30/10/17 4.20pm: Sony has revealed our first look at Destiny 2's first expansion, Curse of Osiris.
The video reveals the expansion is based on the Vex alien enemy, and sees the mysterious Osiris, "the most notorious Guardian in Vanguard history", return. You have to go to Mercury to find him.
Here's the official blurb:
"Curse of Osiris is Destiny 2's first expansion and sends you back to the stars to solve a new mystery. The Vex are on the march, and our only hope to stop them may lie with Osiris, the notorious heretic and most powerful Warlock in the history of the Last City. On your quest to find him, you'll meet new characters, explore new places, tackle new challenges, and earn some sweet new loot.
"Curse of Osiris adds a new chapter to the world of Destiny 2, expanding the universe by adding an all-new cinematic story with new and returning characters, a new destination to explore, Mercury and its Infinite Forest, a new social space to visit called the Lighthouse, new missions, new strikes, new raid content, new free roam activities, a world quest to complete, and more."
Curse of Osiris comes out on 5th December. Expect more soon.