Nekonade Distortion

In Nekonade Distortion, Tatsuki's little sister Kotoko suffers from an incurable illness and spends her days reading in her room. He avoids entering to prevent stress. One night, seeing shooting stars, he decides to share this joy, only to find Kotoko lifeless. Blaming himself, years later, on another starry night, he visits her room again—and she's alive. The next morning, his parents act as if she never died, and his cat transforms into a catgirl. A sci-fi family drama with a philosophical twist, from Whitesoft.