How to open secret LIGHTHOUSE CHEST on Mercury | Destiny 2 Curse of Osiris DLC Easter Egg
Hidden inside the new Lighthouse on Mercury is a secret chest behind a lightwall. The only way to open it, is to find the 5 books inside this room and activate them in the right order.
There is a soft time limit running behind the scenes that makes you start over if you take too long but you don’t have to rush if you know the locations.
After the 5 books for the hidden lighthouse chest are activated you only have to deactivate the firewall that now spawns in the room and you are free to loot the secret lighthouse chest.