Before you can pick up the guitar, you must talk to Bard first.
He's sitting on the ground near a small campfire in Stonewake's Cross, close to the Potions Stall.
Just walk up and speak to him. Once he gives you the quest, the guitar becomes interactable. If you skip this step, you can stand on top of the guitar all day and nothing will happen.
Little tip: a lot of players forget this, so if the guitar “doesn't work,” it's almost always because the quest wasn't activated.

Alright, here's the part everyone searches for. The guitar is hidden in a Secret Cave inside the main cave of Stonewake's Cross.
Follow this simple route:
You'll fall through the greenery into a hidden cavern.
Inside, you'll see a skeleton sitting by the wall. The guitar is on the rocks to the right of the skeleton.
Pick it up, climb the ladder, and walk back to Bard.
Yes — absolutely.
The guitar is invisible or unpickupable unless the quest has been started. Talking to Bard “activates” the item in the hidden cave.
After handing the guitar to Bard, he gives you:
The Unknown Key is the important part. It unlocks a sealed gate deeper in the caves, giving you access to new content and eventually the ability to buy the Arcane Pickaxe. That weapon is pricey, but the quest is required if you want to reach it at all.
Yes, if you want to unlock the Inner Cave gate or buy the Arcane Pickaxe.
If you skip this quest, that whole path stays locked.
No.
The Lost Guitar is a one-time quest.
Once completed, the guitar does not respawn and the Bard will not ask for it again.
If you're speedrunning or making a guide, here's the shortest clean route:
A full loop takes less than one minute once you know the spot.
If you ever find yourself short on time or tools while running this route, you can always make things smoother by choosing to buy The Forge Items online from U4GM in a quick, hassle-free way.
The “leaves wall” is the part people miss most.
Look just left of Nord and Umut — there's a wooden post in the wall and some vines that look decorative. Step onto the leaves and you'll fall through them into the hidden room.
If you overshoot, just walk back up and try again. The spot is small, but you'll get it quickly.
Yes — the unknown key you receive opens the mysterious gate in the Inner Cave.
Behind it is the shop that sells the Arcane Pickaxe, one of the most powerful tools in the game. Returning the guitar is the only way to reach that progression path.
The Bard's lost guitar is a simple quest with a surprisingly sneaky solution. Once you talk to Bard and head into the cave, all you need to do is take a left, walk into the leafy wall, and drop into the hidden chamber. Returning the guitar unlocks the Unknown Key, access to the Inner Cave, and eventually the powerful Arcane Pickaxe. It's a small quest, but an important one if you plan to progress deeper into The Forge.