Curse of Osiris

Curse of Osiris is the first DLC expansion for Destiny 2, and was released on December 5, 2017. Curse of Osiris takes place on Mercury and follows the Guardian's efforts to rescue Osiris from the Vex in order to avert a dark future. The expansion's plot also focuses on the relationship between Osiris and his disciple, Ikora Rey.

Plot
After the defeat of the Red Legion, the battered Last City starts to rebuild all they lost. However, when a terrible Vex plot threatens Mercury, the legendary warlock Osiris calls upon the Guardian to prevent the Vex from assimilating the entire universe.

Story missions

 * The Gateway - Travel to Mercury and the fabled Lighthouse to answer Brother Vance's distress call.
 * A Deadly Trial - Find a way to revive Osiris' Ghost, Sagira.
 * Beyond Infinity - Find out who's behind the Infinite Forest and make it out alive.
 * Deep Storage - Travel deep into the Pyramidion on Io to locate where Panoptes, Infinite Mind is hiding.
 * Tree of Probabilities - Locate the map of the Infinite Forest and take out anything that stands in your way.
 * Hijacked - Head to Nessus to find a processor powerful enough to analyze the data from the map of the Infinite Forest.
 * A Garden World - Find where exactly Panoptes, Infinite Mind is hiding using the Vex mind core you salvaged from Nessus.
 * Omega - Return to the Infinite Forest to destroy Panoptes, Infinite Mind once and for all.

Adventures

 * The Up and Up - Stop the Vex from gathering data on Fallen combat tactics.
 * Bug in the System - Ruin Vex plans to gather data on the Hive and their Sword Logic by eliminating as many of them as possible.
 * The Runner - Stop the Vex from accruing data on a Cabal Colossus carrying important data trapped in a maze.

Strikes

 * A Garden World - Find and destroy a Vex Mind that's reconstructing the Infinite Forest pathways.
 * Tree of Probabilities - Go within the depths of the Infinite Forest to stop a Cabal commander trapped inside a combat simulation loop once and for all.

Raid

 * Raid Lair
 * Leviathan, Eater of Worlds - Travel deep within the underbelly of the Leviathan to find the source of its engine troubles.

Crucible maps

 * Pacifica, New Pacific Arcology, Titan
 * Radiant Cliffs, Fields of Glass, Mercury
 * Wormhaven, New Pacific Arcology, Titan

Locations

 * Fields of Glass, Mercury
 * Hangman's Pass, European Dead Zone, Earth

World Quest

 * Legends Lost
 * Dawning Ghost quest

Trivia

 * The Story missions A Garden World and Tree of Probabilities were reused as the two new Strikes in this expansion, drawing the ire of many players.
 * The World Quest for Mercury had been teased prior to the expansion's release. It is obtainable after completing Verse 10 at the Lighthouse's forge.
 * Curse of Osiris is the first Vex-focused expansion in the Destiny series. The second being Season of the Undying.