The most significant plot twist in "Josee, the Tiger and the Fish" is the reversal of the main characters' physical circumstances. After spending the majority of the film helping Josee navigate the world from her wheelchair, Tsuneo is struck by a car in the process of saving her. He suffers severe leg fractures, and doctors inform him that he may never fully recover the mobility needed to pursue his diving career. This event shatters his dream and plunges him into a deep depression, mirroring the hopelessness Josee felt at the beginning of the story.
This role reversal is the narrative's emotional core. Josee, who has grown immensely in courage and independence, must now become Tsuneo's source of strength. She does this by completing her picture book, "The Mermaid and the Radiant Wings," an allegory for their love. The mermaid (Josee) is given wings by a winged being (Tsuneo), allowing her to see a new world. When the winged being's own wings are broken, the mermaid's love gives him new "wings of the heart." By reading this story to him, Josee inspires Tsuneo to commit to his rehabilitation. He eventually recovers enough to walk again. The ending subverts the original short story's more ambiguous conclusion by providing a definitively happy one. After telling Tsuneo she won't see him when he is discharged from the hospital, she is actually waiting for him. They confess their love, and Tsuneo promises to return to her after finally going to Mexico. The film concludes with his return to Japan, where they share a future together.