When you look at Miyuki and Tatsuya now, it's difficult to see them as anything other than loving siblings. But it wasn't always like this. Miyuki was always uneasy around her older brother three years ago. Even though he was the perfect Guardian, looking after Miyuki while she went about her normal middle school routine, the rest of their family viewed him like a lowly servant. But what worried her the most was that he never expressed any feelings or ideas of his own. However, when danger calls on a perilous voyage to Okinawa, their relationship as brothers and sisters will be irrevocably altered...