Asuna Yuuki accesses Sword Art Online through her school friend Misumi Tozawa, known as Mito, an experienced beta tester who guides her initial days in the death game. Seeking escapism from real-world academic pressures and familial expectations, Asuna struggles upon being trapped, first isolating herself before resolving to fight. She adopts a near-suicidal combat style, battling monsters relentlessly outside safe zones to control her fate. During a mountainous encounter with nepenthes monsters, Mito abandons their party as Asuna faces death, leaving her to be rescued by Kirito. Kirito suggests Mito acted from fear rather than malice, a betrayal that deeply impacts Asuna. Kirito provides healing items and directs her to safety. Later, he finds her collapsed from exhaustion in a dungeon, insists she rest, and brings her to the first-floor boss raid strategy meeting. He gifts her a new rapier and trains with her, refining her combat approach. Their partnership strengthens during preparations for the battle against Illfang the Kobold Lord, with Kirito offering emotional support when Asuna shares her disillusionment with beta testers. At the boss battle, Asuna fights alongside Kirito and Mito. After leader Diabel dies, they defeat Illfang together. Post-victory, players accuse Kirito of withholding boss information, labeling him a "beater." Asuna witnesses Kirito accepting this title to shield other beta testers, including Mito. Mito later apologizes and requests to rejoin Asuna, but Asuna declines, stating she has chosen her path with Kirito. They proceed to the second floor together, formally exchanging names as they depart. The film depicts Asuna’s evolution from despair to determination, highlighting her rapier proficiency and growing independence. Her initial armor includes a dark red leather tunic, copper breastplate, and hooded cape, while the story establishes the origin of her signature braided hairstyle.