(from ebookjapan):

An old apartment building is on fire and an old man is about to jump into it. Shiro, who happens to be passing by, rushes to hold the old man back, but he is unable to overcome the old man's power and is dragged into the burning apartment together with him. In the apartment, Shiro sees a beautiful picture of a battleship.

Following the old man's instructions, Shiro and the old man hastily capture the burning picture on their cameras and escape in the nick of time. That night, the old man, who is supposed to be mortally wounded, comes to Shiro's house. He says that he really wants to see the battleship "Mahoroba," which Shiro had captured with his camera earlier, before he dies. What in the world is the "Mahoroba"?