The Calm Before the Storm

The children climb out of the van in front of an old building in The Middle of Nowhere, Iowa. It was clearly an institution of some kind, not a home or place of commerce, but its former purpose is vague. It's been abandoned for decades, left to its slow erosion, open to the elements and any enterprising animals.

"What is this place?" asks Vera, unable to read anything with her powers damped.