Harry picked up the letter. It was addressed to him. He ripped open the letter, and shouted, ¡°It's from Sirius!¡±
¡°I'd take that gum out of the keyhole if I were you, Peeves,¡± he said pleasantly. ¡°Mr. Filch won't be able to get in to his brooms.¡±
¡°Oh ¡ª yeah ¡ª¡± said Harry, quickly forcing his thoughts back to that first broom ride. ¡°Expecto patrono ¡ª no, patronum ¡ª sorry ¡ª expecto patronum, expecto patronum¡±
And out of the end of his 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. 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.