There was a bush at the very edge of the water. Harry threw himself behind it, peering desperately through the leaves. On the opposite bank, the glimmers of silver were suddenly extinguished. A terrified excitement shot through him -- any moment now -- 

"Come on!" he muttered, staring about. "Where are you? Dad, Mum, come on --" 

But no one came. Harry raised his head to look at the circle of dementors across the lake. One of them was lowering its hood. It was time for the rescuer to appear -- but no one was coming to help this time -- 

And then it hit him -- he understood. He hadn't seen his father or his mother -- he had seen himself and Amelia -- 

Harry flung himself out from behind the bush and pulled out his wand Amelia doing the same. 

"EXPECTO PATRONUM! "they yelled. 

And out of the end of Harry's wand burst, not a shapeless cloud of mist, but a blinding, dazzling, silver animal. He screwed up his eyes, trying to see what it was that ran along aside Amelia's wolf. It looked like a horse. It was galloping silently away from him, across the black surface of the lake. He saw it lower its head and charge at the swarming dementors.... Now it was galloping around and around the black shapes on the ground, and the dementors were falling back, scattering, retreating into the darkness.... They were gone. 

The Patronus's turned. It was cantering back toward Harry across the still surface of the water. It wasn't a horse. It wasn't a unicorn, either. It was a stag. It was shining brightly as the moon above ... it was coming back to him....

 It stopped on the bank. Its hooves made no mark on the soft ground as it stared at Harry with its large, silver eyes. Slowly, it bowed its antlered head. And Harry realized... "Prongs, "he whispered. 

But as his trembling fingertips stretched toward the creature, it vanished.