White Past: Hidden Ambition

Believing Sasuke dead, Naruto lets his fury loosen the seal restraining the Nine-Tailed Fox, and his chakra flares so violently that Haku notes it has become plainly visible when such energy should be unseen. The borrowed power knits Naruto's injuries shut and lets him batter Haku, swatting aside the needle strikes with sheer force. When Haku tries to slip out of his mirror formation, Naruto matches the fox's speed and clamps onto his arm.

A single crushing punch flings Haku through a mirror and collapses the entire ring of ice. Naruto charges to finish him, but the mask breaks away to reveal the gentle boy from the forest, and the sight stops his fist. Haku, calling himself a spent and broken tool of no further use to Zabuza, asks to be killed and recounts his origins. Born in a small village where inherited bloodline traits were dreaded, he discovered his mother's gift as a child, prompting his ashamed father to murder her; when the man turned on him next, the boy's power awakened and killed him instead, and Zabuza later took him in to train him. Meanwhile Kakashi, reassured that only a sliver of the fox's chakra has escaped, unrolls a scroll to end his own fight. Having earlier let Zabuza's blade cut him and coat itself in blood, he summons the Tracking Fang Technique so his hounds can scent out the swordsman through the mist, then readies his one original jutsu, the Lightning Cutter.

The episode adapts chapters 28, 29, and 30 and belongs to the Land of Waves storyline. It delivers Haku's full backstory, framing his devotion to Zabuza against the fear surrounding kekkei genkai, and marks the debut of Kakashi's Lightning Cutter.