First you need to access the Sheikah terminal in the middle of the gear, and second you need to access the chest that’s also moving around the center of the gear. This where the Cryonis rune comes into play. Speak with Sidon and you’ll have to jump on his back as you take out the preliminary defenses of the Vah Ruta. If you don’t have the Phrenic Bow you can still complete this quest, it’s just slightly more difficult.
When you’re ready, equip the Zora Armor, Shock Arrows and the Phrenic Bow if you have it, along with the Cryonis rune. There’s a chest here that contains a Knight’s Shield with considerable durability and 40 defense. Before you speak with him, head to the west side of the dock area, just beyond the bed. You’ll come to a long ramp that leads to the top of the East Reservoir Lake where Prince Sidon is waiting for you. With your Shock Arrows in hand, head back out the eastern exit, but this time head to the right after the long path that leads out of the Zora Domain.
If you don’t have at least 5-10 Shock Arrows, head over to our coverage about how to get Shock Arrows (and the Zora Greaves) before heading into the Divine Beast Vah Ruta.
