As you explore the opening area of Nexomon you should find Salem. Salem is a friendly but mischievous ghost who will give you a little puzzle to complete. You can refuse to do it, but it is pretty easy to finish, and will get you some items. 

Salem will dart around the screen, showing you different routes, and you will then need to go through the same routes in the order. If you get each one right, you pop back onto the same screen in a different place. If you get it wrong, you end up on the screen below the puzzle section and need to begin again. 

The solution to the puzzle is as follows:

  • Side exit on the rightTop exitSide exit on the rightThe bottom left exit towards the eastTop exit

When you get the puzzle right, you will be able to move on to the next screen, where Salem will give you a vault key. There are some other glowing items you can pick up here, and a chest you can open.

You’ll run into Salem throughout the game, and the friendly ghost will have some similar puzzles to solve, each one getting you some useful items. There are other NPCs dotted around the game as well, all of whom will want you to do something that can get you some great items. Be sure to explore off the beaten path to find lots of side quests and missions.