The confrontation begins with Weiss walking out onto a stage for what appears to be a concert. Soft music begins to play, and she begins singing "Mirror Mirror".
The scene then transitions to Schnee Training Room where a large suit of armor rises up and prepares to attack Weiss.
Having just defeated a group of robots for her training, Weiss has a conversation with Jacques Schnee's secretary about what Huntsman Academy she will attend. The secretary tells her that she should attend Atlas Academy, but she reminds him that she has already stated her intention to attend Beacon, to put distance between herself and her family. The secretary lets the Arma Gigas into the room and explains that the Schnee Dust Company put multiple specimens of possession-type Grimm inside of it. He reveals that Jacques wants her to fight it as a "test" if she continues to insist on attending Beacon. He then goes on to state that its strength is comparable to that of a "mecha-suit" and that it is three times stronger than the original model. Weiss states that what the secretary is basically telling her is that she has no chance of winning, but she engages the Arma Gigas in combat regardless.
The Fight ("White" Trailer)
The fight starts as the Arma Gigas stands up and swings its massive sword down at Weiss, which she narrowly evades by back-flipping out of the way. Weiss then draws her rapier, Myrtenaster, and darts forward, landing a hit onto the Armor before briefly twirling and landing.
The Arma Gigas swings again, but Weiss darts behind her opponent, landing several slashes on her foe as she spins. The Arma Gigas responds by swinging its sword horizontally at her, but she manages to block the attack, bringing Myrtenaster up just in time. She is, however, unable to prevent herself from being sent sliding back.
Upon recovering from the attack, Weiss looks up just in time to see her foe in the air preparing to strike at her. As the Grimm swings, she quickly dodges, but it persists in its attack, sending her tumbling back. With white energy gathered on her fingertips, Weiss makes a downward motion to the ground, and a white glyph appears underneath her.
She then dashes forward with inhuman speed, preventing the Arma Gigas from landing a blow, and seemingly teleports around it several times with the assistance of her glyphs, striking it many times in the process. However, when she slows the frequency of her attacks, her foe retaliates by swinging at her, but she leaps over the sword, but is caught off-guard by the subsequent punch, which sends her flying.
Weiss then stands back up and faces the Arma Gigas, blood flowing down the left side of her face. She then assumes her combat stance and turns the revolver to the red Dust and releases the Dust onto her rapier's blade. The Arma Gigas proceeds to charge at her and launches an overhead strike, but she swiftly deflects the blow with her rapier, causing the former to stumble back.
Weiss spins as she changes to another slot on Myrtenaster's revolver and stabs the blade into the ground, which sends a wave of ice forward. This freezes one of the Grimm's feet in place, immobilizing it. It then swings at her as she runs forward and jumps, landing perfectly onto the sword. With Myrtenaster glowing yellow, she rolls along the sword and slashes at her foe, destroying the ice crystals and knocking her opponent's weapon away.
She creates a white glyph underneath herself and rotates the revolver once more as the Arma Gigas tries to punch downwards at her. However, she evades the attack and causes the glyph on the ground to explode, launching her foe into the air. Weiss then sends six beams of blue energy at the Grimm, locking it in midair.
With one final glyph-augmented leap into the air, Myrtenaster glows with white markings along its blade and Weiss creates yet another glyph, which she uses to dash at the Arma Gigas, cutting right through it. As the Grimm falls through the air, some sort of white energy is emitted from its joints and helm. Weiss lands in a crouch, but stands up as the suit of armor hits the ground and shatters into ice shards.
- Chapters 3 and 4 of the RWBY manga depict the battle with additional preceding detail and more of Weiss' perspective.