As soon as you reach the Sea People Village in Dave The Diver, Tenzhin, the ruler of the village, will ask you to gain their trust by completing various tasks. Once you've acquired 100 credits from these quests, he'll ask you to return the next day and retrieve the key to the Glacier Passage.
To get this key, you'll head over to the Abandoned Cave alongside Suwam, but he'll ask you to go inside alone. This will be one of the hardest areas in the game since you can't fight the enemies inside.
How To Get Past The Abandoned Cave
As soon as you enter the cave, you'll see a fish being eaten alive by a Gadon. Thankfully, it'll be on the other side of a robust cage for now. Go down from this area, turn left, and then go down again until you reach the room with a mural on your right. In this room, you'll have to place the stones in the following ways to get past:
- Place the rock with a circle on it on the leftmost platform in the room.
- In the middle platform, place any of the two normal rocks (without any shape) first and then place the square-shaped rock on top.
- Finally, the rightmost platform will take one normal rock and then the cross-shaped rock.
Of course, the game wouldn't let you go that easily. An earthquake will occur and all the Gadons in the area will go free. Pick up the key and head as far up as you can as soon as you exit the room. Once the Gadon goes near the room you just came out of, sneak behind it and go all the way to the left.
While heading up from the left path, you'll find another Gadon in the way. You have to keep heading straight up, but make sure you wait for this Gadon to go all the way to the right side before you go past. Go as far up as you can and the camera will pan to another Gadon patrolling near some statues.
Wait for the Gadon to go all the way to the right and then quickly sneak to the first statue. As you get close to the statue, you'll see a button that'll let you hide behind it. Now, wait for the Gadon to the left and you can get past this room using the same process. Once on the right side, go down and navigate past some spike traps.
As soon as you get past the traps, turn right and go down to hide from the fourth Gadon. It's optional to get past the statues here since you'll get a Silver Bowl at the end, but you can also continue downward. Get past a few more traps here and go all the way up to exit the Abandoned Cave.
Outside the cave, you'll have to fight John Watson again. Go to the bottom of the sea floor to find a Baseball Bat in a chest. You can charge this bat up and use it to deflect Watson's missiles back to his armor and defeat him. Pick up the part of his armor and head back to Tenzhin to let him know about what you found.
Complete Old Cave Guide
On the night after you exit the Abandoned Cave and Tenzhin asks you to come back on the next day, there'll be a cutscene where you'll play as Dr. Bacon. Once you enter the Old Cave in this cutscene, you'll have to put a specific code on the right side. This code will contain three random symbols.
To find out the symbols you're supposed to put, go to the murals on the left side and pay attention to the letters written in red. You're supposed to put these letters in the code in the same order as the murals. This will unlock a chest and you'll have to fight a few pirates to take it back safely.