You are Ron

You decide to try and ditch Lavender as she'll probably end up messing the operation up anyway. You see Lavender in the corner packing a bag full of food and Weasley's Wizard Wheezes products. Speaking of which, you decide to snatch one of their new products for picking up chicks. You run into the other room, and dig through the boxes. AHA! You pick up a box with a picture of a curly mustache on it. The box reads, " 'I moustache you a question' Mustaches. Great for picking up witches!" That sounds about right. Now is the time to make your move. You put on the mustache and slam your hand on the wall right next to Lavender's head. At first she is started, then delightfully intrigued.

"Lovely Lavender, I moustache you a question," you say in a ridiculous accent as you devilishly twist your fake mustache. Lavender is in a fit of giggles. "Will you meet me in The Leaky Cauldron in five minutes? I MUST HAVE YOU!"

There are happy tears in her eyes. "Oh, Won-Won" she whispers. Immediately, Lavender runs out of the door. You rip off your moustache, quite pleased with yourself.

"Well, that gets rid of that problem. Hey, let's find that Horcrux, shall we Cho?"

"I'm not sure if that was the smartest--"

"Cho! I know Lavender. She'll be just fine."

"I'd really watch your Karma."

"What the bloody hell did you just call me?"

"Nevermind," Cho says. "Well, let's get going."

You and Cho use Floo powder to get to Knockturn Alley in disguises (those mustaches are handy!) and have been in Borgin and Burkes for a good 20 minutes. There doesn't seem to be any leads to help you find the Diadem. Suddenly theres a low rythmic sound coming from a far, and what is that? It sounds like musical instruments? You hear yelling and chatter outside and everyone, creepers and all are running in one direction back toward what looks like Diagon Alley. You and Cho decide to follow.

You push yourself to the front of the crowd to see the most bizarre event in your entire life. People in bright outfits, stilt walkers, jugglers, dancers, and at the front-- Lavender?! She seems to be singing about love lost-- Merlin's beard, how do all these strangers know all the words? You and Cho's jaws have dropped to the ground. Next thing you know, Lavender and Voldemort are on the roof of Quality Quidditch Supplies dancing and singing something about...."to dance again?" You don't know whether to be amused to see Voldemort dancing, or the frightened by the fact that everyone around you knows the words and choreography.

The number ends and everyone reacts by laughing hysterically as if they've all known each other for years. Voldemort commands the attention of the crowd:

"Fellow witches and wizards who have joined me in the jubilant celebration of human emotion!" he yells as the crowd responses in jubilant cheers. Up on the roof, Lavender spots you in the front with that same silly mustache you tried to lure her away with.

"Look, Voldemort, THERE HE IS! WON-WON! He's the one who scorned me!" Lavender points as the entire crowd looks directly at you.

"SEIZE HIM!" Voldemort orders.

There's nothing you can do but run for your life. The search for the Diadem has failed.