The battleship Amanohara picked up a foreign castaway. It turns out to be Sophia, the woman Shintaro was engaged to when he was stationed in Russia as a diplomat. However, perhaps due to the shock of her drifting, she loses her memory and looks like a different person. The girls who want to encourage Shintaro decided to fold a thousand paper cranes for Sophia. Sarasa is the only one who can't fold the crane well...