
Inside the ruins walk over all the panels on the ground, causing them all to light up and the statue to react. This will cause the door to open, letting you inside. The clue to open the door to this ruins is: "Let ring the piercing note that will wake the giant of steel." To open this door you simply need to press in the left control stick and whistle while standing near it. Approach the ruins and interact with the door, which is locked but can be opened by solving a riddle.

Exit Freezington from the side of Peony's house then stay right as you descend. Iron Ruins can be found near the top of Giant's Bed, just after the icy ground transitions to grass. Make your way to the steel temple where Registeel is resting, known as Iron Ruins. "Let Ring The Piercing Note" How to Catch Registeel Approach and interact with the statue to enter a battle with Regice. Luckily you can catch a Cryonagal just outside the ruins, so quickly grab one if you don't have it, set it as your lead, then approach the door again to enter. The clue to open the door to this ruins is: "Walk together with a living crystal of snow." To open this door you need to have Cryonagal set as your lead Pokemon.
