There are several new activities and events in Destiny 2‘s latest update, Season of Dawn. They all revolve around Osiris and the Sundial, which are on Mercury. You start working with Osiris shortly after you speak to Ikora at the Tower and start the A Matter of Time quest. Eventually, you’ll have the chance to grab An Impossible Task from Osiris, and there’s a quest step called Corridors of Time.
You can do this quest alone. However, it helps to bring a fireteam in to make it go faster.
Note: There is a new Corridors of Time Quest as of Jan. 14. You can learn about that quest over here.
The Corridors of Time happens after you return to Osiris and turn in the Vex components you acquired from the Big Vex Hunting section of the quest. You won’t have a Corridors of Time quest show up in your quest menu. However, to the right of Osiris, you’ll notice you can now interact with the Sundial to start this quest. Approach it, and start it.
The Sundial interacts with the Shotgun you crafted from the first quest that you did before An Impossible Task called Recovering the Past. Proceed forward into the white room and go through the gates. During the first portion, there’s a room full of Vex you need to kill. Every so often, a small robot traps you a shield. You can shoot your way out of it, but if you hit the drone before it makes it to you, you won’t have to deal with the shield. Kill all of the Vex.
You will go through several of these oddly lit rooms and make it through the unblocked doors with glowing white light pouring from them.
Eventually, you’ll reach a point where you receive a new quest objective: Search for Saint-14.
Now, you’re facing off against older Vex and Fallen as they attempt to make their way to Saint-14 and take him out. Proceed through the mission destroying all of them and anything in your way. When you find Saint-14, he is surrounded by Fallen is using a shield to protect himself. Take out the Fallen and help him out, and any Fallen that land there.
After the first wave, the House of Rain Servitor and House of Rain Walker spawn into the fight. Take out the Servitor first before you find the Walker because the Servitor shields it. After you kill these two, all of the minions despawn. Walk up to Saint-14 and speak to him, arming him with the Perfect Paragon. After, you’ll return. These steps conclude part 1 of the Corridors of Time quest.
The next step of the quest will release at a later date.