The villain Diablo is back, and wants to defeat the princess from the Inhumans, the Medusa sister, Crystal. For that, he brings one special elemental specifically to end her once for all, since her powers are stronger against Diablo. This elemental constructs turns the heroine into a solid gold statue with a simple touch.
A few pages after that she backs to normal without any explanation. Probably because Diablo was defeated, she back to normal.