As you wander through the spooky forest to the south of the Orphanage, you will come across a ghost with a quest for you to do. If you interact with him, you will discover that this poor chap has an embarrassing reason why he needs to hang around. He needs someone to delete his browser history before he can rest in peace. The good news is that his house, and computer, are located in the Immortal Citadel, which is where you need to go anyway.
To get to the Immortal Citadel, go up the steps to the right of the Ghost, then exit the screen via the north exit. You will see a stone bridge, and just keep walking north up the bridge, and eventually, you will come to a giant hollow tree trunk. Head through here to get to the Immortal Citadel. On the way, an NPC will crash into you, followed by a flustered postman with another quest for you, but can ignore this for now.
Turn right and walk all the way to the next bridge, cross it, then head north, and this will bring you to the ghost’s old house. Head inside and you will find the computer. Interact with it to delete the browser history and you will have done what the ghost needed.
Now, you can either automatically warp back to the ghost, or finish up in the Immortal Citadel and head back there on foot. This quest will get you 350 Gold, and some special Nexomon Traps so is well worth doing.