The electrical system in the barn doesn't take well to the presence of an angel, and sparks shower down as Castiel walks inside.

It does nothing to slow his stride. Nor does the mosaic of talismans, sigils, and devil's traps on the walls and floor. His eyes flit to either side for a moment, appreciating the work that has gone into it. But only momentarily.

Castiel's main focus is on the man standing in the center of it all.