Caspia, a thousand-year-old spirit cat who has taken human form as a youth, is coveted by factions far and wide as an "experimental subject". Cornered in a rainy night, he stumbles into the arms of Vincent, a tech CEO with underworld bloodline. From mutual wariness and misunderstandings to repeated rescues and growing affection, the two eventually open up and fall in love. Vincent fends off the board’s schemes, shielding Caspia so he can set aside his old self. Caspia steps into the spotlight in his true form, winning the whole city’s recognition with his gift for painting.