The central tragic twist of "Look Back" is the sudden and violent death of Kyomoto. After she and Fujino have a falling out over Kyomoto's decision to attend art school, Kyomoto becomes the victim of a random mass murder at the school, attacked by a man with an axe who claims his art was plagiarized. This event shatters Fujino, who is overwhelmed with guilt, believing that if she had never encouraged Kyomoto to leave her room, she would still be alive.
In her grief, Fujino tears up the comic strip that started their friendship. This act triggers an extended fantasy sequence where she imagines an alternate timeline. In this "what if" world, she never gives the comic to Kyomoto, their friendship never happens, yet Kyomoto still decides to go to art school on her own. The attack still occurs, but in this version, Fujino happens to be nearby and saves Kyomoto with her karate skills. In this imagined reality, a grateful Kyomoto draws a 4-koma strip titled "Look Back," depicting Fujino as her hero. A gust of wind blows this strip from the fantasy timeline into Fujino's real, grief-stricken present. Seeing this comic—a manifestation of her own need for catharsis—and remembering how much Kyomoto loved her work, Fujino realizes that wallowing in grief is not what her friend would have wanted. She finds the resolve to continue their shared dream. The film ends with a lingering shot of Fujino back at her desk, drawing once more, with Kyomoto's "Look Back" strip taped to the wall as a memorial and a source of motivation.