An at first silly, theoretical experiment by Rei goes wrong, and all of a sudden, Haru turns into a sleek, black cat. Who gets lost. Rin finds this strange cat who loves swimming in water, and intrigued, he takes Haru home. In turn, Haru slowly starts to realize that Rin too has secrets, attachments, thoughts, and feelings he doesn't want to share with anyone. RinHaru. Sharkbait.