Destiny 2's Mysterious Box quest is an Exotic quest found as part of the Black Armory DLC, the first expansion in Destiny 2's second year.
Right now, as the box itself describes, it's a bit of a mystery, with four Mysterious Box quest steps currently available and unsolved.
Though if you are playing the Black Armory DLC, it's well worth picking it up - as it's most likely tied to other activities along the way.
How to find the Mysterious Box in Destiny 2
First, you need to own the Black Armory DLC, which is part of the Destiny 2 season pass.
Play through the Black Armory quest steps, until you have returned to Ada-1 and are told to go visit the Volundr Forge.
Proceed to the Forge as usual (by heading to the EDZ's north-east most starting location, setting the Forge as the objective on the map and following the waypoints through the nearby tunnel) until you arrive at Smidur's Cavern.
The cavern has a large ravine below the cliff edge right in front of you, where you have to jump across to the Forge. However, if you look to the left of where the broken bridge is, you'll find a ledge lower down.
Go round the other side, and jump down to it.
Turn around, and you'll notice another ledge opposite, as well as a cave.
Head inside this cave and you'll come to two crates. The larger left one is the one you're going for. Investigate it, and the Mysterious Box will be yours.
You can now begin the Mysterious Box quest.
The Dawning returns with recipes and ingredients, following on from recent additions including Black Armory quest steps, Mysterious Box quest and the new Scourge of the Past raid usher in the start of Year 2's first DLC. Completing the above requires some Destiny 2 levelling of course, and it helps if you know how to complete the latest Ascendant Challenge and Blind Well and Oracle Engine Offering activities. There's also Exotics such as the Ace of Spades, the Chaperone and Malfeasance to unlock.
What do we know about the Mysterious Box quest and opening Locks so far?
The Mysterious Box quest steps have you involve four locks. The description is as follows:
"An ornate box with four locks. Each lock has a different symbol emblazoned on it: a hand, a butterfly, a fishhook, and a Black Armory insignia."
There are then four steps to complete:
- Fishhook lock opened
- Butterfly lock opened
- Hand lock opened
- Black Armory lock opened
Right now, what these four locks relate to is a bit of a mystery. Since the Black Armory DLC has just launched, and it's yet to be completed, the running theory right now is it's gated behind completing all four of the Forges arriving in the coming weeks.
Going by Bungie's schedule, these are:
- Volundr Forge (December 4th)
- Gofannon Forge (December 7th)
- Izanami Forge (December 18th)
- Niobe Labs (January 8th)
So four Forge activities for four Mysterious Box quest steps. Quite plausible, right?
Of course, there might be more to it than this. LessThanZero86 on reddit has found two other mysteries that possibly relate to the Mysterious Box - one, an interactive console with one of the above symbols that seemingly does nothing, and two, is using the Hammerhead machine gun's sights to reveal symbols in the world:
These might be part of opening the Mysterious Box, or tied to other Black Armory secrets entirely. It's early days right now - but either way, it's worth starting the Mysterious Box quest when you can, in the event one of the four 'lock opened' steps will take place as you're playing elsewhere.