Make your way to the Hall of Doors, and then take the door that leads to the Old Watchtowers — it can be found by heading south down the stairs from the main lobby, then taking the stairway to the west. Once you’re through the Old Watchtowers door, you have three things to do: light all the braziers, find the owl, and find a secret hidden just outside of Betty’s Lair.
From the door, drop down twice to the southeast, then head to the northeast side of the tower and you’ll see a brazier (1). Light it, then whack the nearby crystals to recharge your energy. Climb up the two ladders, then walk northwest out onto the broken wooden bridge. To your west you’ll see another brazier (2); light it, then hookshot across to the next tower.
Head northeast across the wooden bridge, and drop down heading north just past the large flag. Continue north a bit and you’ll see the 3rd brazier (1). Light it and continue southeast, hookshotting to cross the gaps and reach the ladder. Climb it, plant a seed in the nearby pot if you haven’t yet, then light the brazier to the east (2).
Now head northwest, up the stairs, then up the ladder. Note the wooden bridge that leads northeast — you’ll come here once you’re done lighting the braziers. For now though, drop down the ladder to the southwest, and continue forward until you reach the next ladder. Climb it, and then hookshot to the ankh southwest of you. Stand just west of the ankh and aim northwest, and you’ll see another brazier. Light it, then continue southwest, and drop down near the next ankh.
Continue further southwest, then go northwest at the next ankh. Plant a seed in the pot by the elevator, then take the elevator up. Hookshot to the tower to the northwest, then go east past the windmill and hookshot to the ankh southeast of the wooden walkway. Drop down to the platform below, then light the final brazier to the northeast.
Hookshot to the ankh east of you, then hookshot southeast, and head northeast a bit before dropping down onto the path.
Go south and then east, climb the ladder, and continue northeast across the wooden bridge. Head through the doorway and grab the Ancient Tablet of Knowledge in the room beyond. Instead of backtracking, just quit to the title screen, load your save, then go through the door back to the Hall of Doors. Enter the westernmost door, which leads to Betty’s Lair.
Head southeast to leave Betty’s Lair, plant a seed there if you need to, then break the crystals east of the doorway to reveal stairs to the north. Head up the stairs, and you’ll see a moon symbol on the ground near a rock wall. Stand in front of the wall and press [E] to open the doorway and head through. Grab the Mysterious Locket, then go back down the stairs the way you came.
Head southeast from the doorway across the bridge, drop down the ladder, and head east across the ice. Go up the stairs there, and go north onto the wooden walkway to make your way around the wall. Continue southeast, through the crystals and down the ladder, then once again head northeast onto the wooden walkway that leads around the windmill. Continue on the walkway to the elevator, and ride it up.
You’ll have to make your way across the ice now for a bit (there’s only one way forward), dropping down, taking the ladder up, and hookshotting across the gaps. There’s a few enemies on your route, and that pesky laser is still there, but it shouldn’t be anything you can’t handle.
Once you’ve made your way through the icy section, you’ll have to break a few crystals, drop down, and hookshot across one last gap. Just ahead you’ll find an owl chilling in a watchtower — interact with the owl and it will give you a shard of an Ancient Tablet of Knowledge. You can now quit to the title screen, then reload your save and head back into the Hall of Doors.
Once you do so, take a look at the door that leads to the Old Watchtowers. If you’ve successfully found all the secrets and filled all the seed pots, it should no longer be glowing pink like the other doors. If it’s still glowing, go back and run the route again, making sure to fill the seed pots when you can (and you can check our full walkthrough of that section for secrets as well).