The rebellious Musashi has been defeated, and the students from Yokosuka Girls' Marine High School have returned home safely. However, the Harekaze suffered critical damage during its final clash with the Musashi and might not be able to sail again. Furthermore, rumors are circulating that the Harekaze-class will be disbanded because it lacks a ship. Attempts by other classes to recruit members from the Harekaze's crew only make the situation more uncertain. The solution to this dire problem might lie in the sealed orders that Kouko Nosa, the secretary of the Harekaze, is supposed to deliver to the crew. But time is running short...