The alert came out through the magical networks, and Harry just happened to be the nearest auror to spot the incoming threat. "Out of the way! Get inside!" He was shouting to people, hurrying down the road toward the threat, wand out just in time to see the newcomer use her own form of magic- something he'd not seen before.
And for a moment, he slowed and stared in awe. Wandless magic. A spell he didn't recognize. There was a moment the dragon seemed baffled too as its flames died down. Then, it regrouped.
"Protego!" He shouted before it could strike again, casting a shield over the few people still outside, including Hope and himself. It blocked the beast long enough to push him back, keeping its claws from swooping in on them.
And it gave them just a moment. Harry glanced at her. "What else can you do?" He needed to act quickly. Just two of them against a dragon- all they had to do was scare it off.