橫濱港
Umi Matsuzaki is a 16-year-old high school student living in Coquelicot Manor, a boarding house overlooking the Port of Yokohama in Japan. Her mother, Ryoko, is a medical professor studying in the United States. Umi runs the house and looks after her younger siblings and her grandmother. Each morning, Umi raises a set of signal flags with the message "I pray for safe voyages".