You can find North Hyrule Plain Cave southeast of New Serenne Stable, which is near Sinakawak Shrine.

Cave Location

North Hyrule Plain Cave can be found at -1188, 0642, 0072, which is southeast of New Serenne Stable, which is near Sinakawak Shrine. There is another entrance at -1236, 0768, 0099.

Explore the Cave

The entrance of the cave is guarded by Like Likes. After you defeat them, use Ascend on the ledge that one of the Like Likes was hanging from.

Down the tunnel, defeat the Horriblin. The path will go west from here, but before you go up the slope, go through the waterfall where you can see some glowing mushrooms. In the room that you find, open the treasure chest to get the Climbing Gear, one of Misko's Treasures.

Exit the Climbing Gear room and go up the slope that leads west (or just use Ascend from where you got the Climbing Gear). Here you will find a Bubbulfrog.