There is actually a secret Easter egg mission! I don't know if I'm the first discoverer or not but its exciting. I was wondering around in old Russia when I found a poster on the wall of a loot chest room. The poster had an image of a blue engram and above it read "Return". After about 30 minutes of searching a found a blue engram and brought it back to the poster. It then gave me an option "hold x to trade". After completing the trade process I heard voice that sounded like the voice of the Queen from the reef. I couldn't make out 100% of what she said, but it then gave me a message to report to the post master at the tower. It gave me a bounty lead and the bounty was to kill 1 of many types of enemies. After finally completing this I handed in the bounty and my reward was a blue engram. It was useless to the cryptarch but I had an exclamation point above earth so I went back to patrol cosmodrome. I figured I had to go back to the poster so I did and what i saw there was the same poster so I did the same trade as before and received a legendary engram. I still couldn't hand it in to the cryptarch but I had an explanation point above Venus but I have no idea what is next. I'm stuck with this engram and can't cash it. Anyone? Help me continue it!?