Bungie recently added a quest to acquire the Sleeper Simulant heavy fusion rifle into the game. I wrote a guide on how to get it here.
Today, the studio has revealed that the most recent patch has come with one hidden addition: an Exotic Pulse Rifle called No Time to Explain. Anyone who's played Destiny will recognize it as a quote from the Stranger, who gives you her pulse rifle after you complete the original campaign.
In addition to increasing Nightfall rewards and fixing the Shadowshot glitch, the studio has enabled a secret quest in the daily Heroic mission, Paradox.
Join the Daily Heroic Story, "Paradox," and while doing so, be sure to collect the three hidden Ghosts from the lost Guardian Praedyth. When you've discovered them all, a secret portal will open. When you enter the portal, you'll have to fight a Taken ultra, at which point you will receive the final Ghost shell that you can return to Lakshmi-2, the Future War Cult representative at the Tower.
This following video guide by DattoDoesDestiny will show you all the locations of the Ghosts.
All of this could be done in previous times when the Paradox mission was set as the Daily Heroic. But today, you will be given a new quest from Lakshmi-2 called "Not Forged in Light," another quote by the Stranger.
The quest will require you to align yourself with her faction, so you'll need to abandon your old faction (don't worry, you can return to them later). You do not need to gain a rank with the FWC. The mission will not show up immediately, so you might have to wait until Paradox becomes the Daily Heroic Story again. It appeared in a week for me after the weekly reset on Tuesday.
NOTE: Don't waste time donating Motes of Light or anything else to FWC before you get the quest to donate your tribute. I got the quest to donate tribute to the FWC even though I was already rank 19.
Once you do so, she will tell you to kill a Taken Minotaur, which drops a specific item called the Simulation Core that you need to continue. Any Taken Minotaur will do, so head to Mars or Venus or any number of missions where Taken tend to spawn—such as Paradox. You might as well head there.
Players from Year One will find themselves at home with this one. You'll have to participate in the actual Vault of Glass raid and kill Atheon for an ingredient. Just head there in Normal Mode.
After you kill Atheon and get what you need, you'll embark on a mission to the Cosmodrome called Shadow at Twilight. Like the one mission to acquire the Sleeper Simulant's IKALOS core, this is a single-player only mission. You can't bring friends. There, you'll have to find a chest and loot it.
The mission takes place in the Twilight Gap crucible map, so just head on over to one of the points where chests spawn. As you spend time on the map, you will steadily lose vision until you go blind, so step into the Pools of Light to clear your sight.
Once you find what you need, return to Lakshmi-2 and embark on the final mission : Blood of the Garden. Your task? Killing the Groundskeeper.
To lure him from his hiding place, kill the adds (most of which are minotaurs), filling his anger meter, until he shows up. He will disappear when his anger goes down, so keep killing adds during your fight with him. To get this done easily, have one player handle the minotaurs while two others focus their attacks on the Groundskeeper.
Finally, return to Lakshmi-2 and get your reward, No Time to Explain. Enjoy!