“Could this be… a kiss?” So uttered the girl as she regained consciousness. She took out a notebook labelled "Wishlist" and checked off an item. The list read "Kiss", "Meet family", "Eat lots of tuna". "That just now… wasn't it a kiss?" To clear up any misunderstandings, it was no kiss, but mouth-to-mouth breathing. I had only intended to save her as she lay unconscious on the observation platform, and yet… My name is Nanami Kanata. All that's left of my family is my sister Yui and our caretaker Asahi, who works as a sister in a nearby church. It was supposed to be just another ordinary day. "You're back." When I came home later that day, the girl was waiting for me. Her name was Haruka. We had the same eyes, hair, aura, and blue feathers that served as mementos of our father. It was only natural: Haruka and I were fraternal twins. It was the beginning of a heartrending love story with a tinge of mystery.