In a futuristic world where humans and mermaids coexist, Stephan, a mild-mannered office worker at a shipbuilding company, whose life is upended when he is suddenly proposed to by Chao — a princess from the mermaid kingdom. With no time to make sense of what’s happening, Stephan soon finds himself living with the unpredictable, wholehearted Chao. As her sincere love begins to…