Gravity breaks, and so does every rule about what an ONA should look like, Bubble moves like nothing else on screen, parkour that feels like dancing, backgrounds that breathe, a Sawano score that makes silence hurt more than noise. The plot barely holds together, and it doesn't need to. You're watching two kids fall in love inside a city that's already forgotten them, and the animation does what the story can't: it makes you believe something was real here.

Tokyo's gravity has shattered. Massive bubbles drift through the sky, warping the laws of physics and isolating the city from the rest of the world. Young people orphaned by the catastrophe now squat in the abandoned capital and compete in dangerous parkour team battles, leaping from building to building. Hibiki is one of these runners, a gifted ace known for pushing boundaries until they snap. When a reckless move sends him plummeting into the gravity-bending sea below, a mysterious girl with strange powers, whom he comes to call Uta, pulls him back to safety. Afterward, both hear a strange sound that only the two of them can perceive. Why Uta has entered Hibiki's life becomes a question in its own right, and their meeting begins to reveal the truth behind the disaster that reshaped their world. Romance and supernatural mystery intertwine in this sci-fi sports story.