Darkness gives way to reveal the words:
"Everyone is entitled to their own sorrow, for the heart has no metrics or forms of measure. And all of it... irreplaceable."
The black closes in again just as new text appears:
ROOSTER TEETH presents
and an amplified voice is heard saying:
Announcer: "Ladies and gentlemen, please welcome... Weiss Schnee."
A young girl in white with a barely visible scar over her left eye walks out on stage into the spotlight as a piano plays the opening of "Mirror Mirror" before a crowd of people, occasionally taking pictures from their stands around the white castle they appear to be in. She closes her eyes and begins to sing.
Weiss: "Mirror, tell me something. Tell me who's the loneliest of all..."
While she sings, the view sinks down into her scar-free reflection on the stage, the world tilting until she opens her eyes and finds herself in another place, the light and shadows shifting until a warrior in giant armor with an equally massive broadsword appears before her. She backflips just as the Giant Armor brings its blade down on where she was, and the song continues as her flashback takes over.
Weiss (singing off-screen): "Mirror, tell me something. Tell me who's the loneliest of all?"
Weiss unsheathes her own rapier, Myrtenaster, and darts forward, getting a hit on her enemy before twirling into a landing. The Giant Armor swings again, but she dashes away and lands several spinning slashes on the creature. It retaliates when she uppercuts into the air, arcing its sword around and hitting Weiss' rapier, which she brings up just in time to merely knock her back. When she slows down, Weiss looks up to see the Giant Armor leaping into the air and hurling the sword down on her, then swinging it back up in an effort to get its fast-moving target. It finally hits her blade again, and she is knocked away until she rolls back on her feet.
Weiss (singing off-screen): "Fear of, what's inside of me. Tell me can a heart be turned to stone?"
With white energy now gathered on her fingertips, Weiss motions to the ground beneath her, and a snowflake symbol appears that propels her forward at extreme speeds. Despite the Giant Armor's attempts to slash at her, Weiss disappears and reappears all around it, leaping through the air using her glyphs and landing a blow with each pass.
After a slash to the face, the Giant Armor aims at Weiss' feet, who leaps over it and gets an undefended fist to her head. Weiss is launched yet again, but this time, her attempt to get back up is weak and unsure. A worried Weiss closes her eyes, and in the real world, the spotlight suddenly cuts out.
The moon makes itself known when the clouds in front of it pass, showering Weiss in its light as she sings, eyes still closed. In her mind, she stands back up, eyeing the Giant Armor with blood trailing down the left side of her face, and holds out her sword, spinning the revolver in the hilt until a red energy appears over the blade. The Giant Armor runs up and drops its sword on her, but it meets her rapier and is deflected off.
Weiss (singing off-screen): "Mirror, mirror, what's behind you? Save me from the things I see! I can keep it from the world. Why won't you let me hide from me?"
Weiss switches it up and spins, a cyan light now creating a wave of ice when she strikes it into the ground that freezes the Giant Armor in place. It swings again, but Weiss runs ahead and jumps on the sword. Myrtenaster is now glowing yellow, and she rolls on the broadsword and slashes at her foe, destroying the ice crystals in shards of purple but impaling its weapon into the ground. She rotates the hilt again and a snowflake circle spins under her when the Giant Armor tries to hammer its fist down on her, but she rolls out of the way and activates the glyph, launching the warrior up into the air and becoming trapped by Weiss' beams of blue energy.
Weiss (singing off-screen): "Mirror, mirror, tell me something. Who's the loneliest of all?"
With one final leap into the air and her real self singing the last lines of her song, Myrtenaster glows with the white markings on its blade and Weiss descends onto the Giant Armor. When her attack is done and she lands in a crouch, the black hollows of the enemy light up and crash to the ground in a shower of ice and snow behind her.
Weiss (singing off-screen): "I'm the loneliest of all."
Weiss gets up and closes her eyes, finishing Mirror Mirror to a gentle shower of snowflakes and a roar of applause from her audience. She opens her eyes and looks around as if in a daze, then peers up at the slightly-scattered moon above.
She dips her head and bows to the crowd as the curtains close around her, followed closely by RWBY's title and the silhouettes of its characters, Ruby Rose and Weiss Schnee. The screen changes to falling snow and an announcement to "SEE THE PREMIERE at RTX 2013: AUGUST, TX JULY 5-7" appears before a snowflake disintegrates the words.