Casting a patronus

I'm a new student at Hogwarts School of Witchcraft and Wizardry. The school isn't quite the same as was described in the books, but still has similar characteristics.

I'm on the top of a tower, having a long conversation with a girl walking around doing errands down in the town below. As long as she stays in sight range, we can hear each other loud and clear. She skips around as she moves like she couldn't be happier. She eventually moves out of range. I can't talk to her anymore, but I still have an important message to tell her! Then it comes to me... I'll use a patronus! I remember from reading Harry Potter's book that they would sometimes get a message from members of the order using a patronus. I decided to give it a try. I tried to remember the things that I had read from when Dumbledore's Army was practicing, and gave it a shot. I pointed my wand forward and yelled expecto patronum! Nothing happened. Hmm, maybe my thought wasn't happy enough. I raked my mind for something happier to think about, but not much came to mind. expecto patronum! Still nothing. I probably said it too fast, was holding my wand wrong, didn't wave it right, or didn't have a happy enough thought. Or all of the above. I adjusted how I held my wand, this time extending my pointer finger down the length of the wand. My wand was weird in that it has a knob... an egg-shaped piece of wood on the end where you hold it. I try several more times. Finally, a wispy blue mist emits from the tip of my wand. -sigh- How frustrating. I realize what a novice I am at magic.

Suddenly someone else's bright blue patronus appears by my side in the shape of an overly-large male human head. The amount of detail is incredible. I can even see the whiskers on his face. "You can't speak for yourself, can you," I ask it. It jerks back for a moment, as if thinking, and then changes into the form of a female professor. In the professor's voice and words, the patronus explains to me how it can only relay messages that have been previously been uttered. Oh, so thats why you can use it to send messages... it can repeat what you tell it.

I keep attempting to cast a patronus. Now other students are around too. The center of the marble column to my right vanishes, and I point my wand at the student behind it, which scares her. "那看起來很黑 (that looks really dark)," a voice says from behind me. I turn around to see a Hermione-looking girl behind me. I quickly put my wand down. A tall, thin professor behind me says in his deep voice, "yes, now is the time when all students are choosing to be light or dark." I know that they mean good or evil. I run to look for my best friend. I want him to be on the white side too, like I am.

The girl comes with me, and I continue conversing with her in Chinese. I start noticing that no one is wearing robes, but instead they are wearing sweaters of different colors. Where I had been, everyone had been mostly wearing white or black. I look down at my chest and see that I'm wearing a deep red colored sweater. As we walk out through the wide entrance of the building, I see for the first time several girls wearing sweaters with a mix of black and neon green. We leave the building and come to the top of a ledge. Looking over the rail, I see the next building over has four lines of students entering the building, one line for each sweater color, black, white, green, and blue. The blue line is shortest and is moving the fastest. It's probably lunch time. Instinctively I know that the blue line is mine, and I'm pleased that I won't have to wait so long.