A couple of minutes later they were flying again, following Flash through the shield and towards the glittering spire of the crystalline castle at the very centre of the Empire. It glowed from the inside as the energies that normally went into the aurora of positive energies the Crystal Heart produced, were channelled into the shield protecting the city. Thousands of Crystal ponies clustered around the castle, waiting for news, but the area directly beneath the castle remained clear, allowing Princess Cadence and her entourage to work unimpeded.