A beautiful day Rokurou, a student, was to masturbate when a beautiful girl knocks on his door: You need a virgin? And so begins the story. Rokurou did not know what it was that this beautiful girl was a millionaire family.

One Room 2nd Season special included on the BD release of the main show. It follows bedroom 'role play' scenarios you have with the girls and dream scenarios you have while asleep near the girls.

Around the the 37th year of the Meiji Era (1904), in the midst of the Russo-Japanese war, the small Japanese army, in need of assistance, uses its special flying (thanks to a benevolent demon) ship, the Amanohara, to attack Russia's major base at Port Arthur (Lushun). Umakai Shintaro, a Russian diplomat originally from Japan, defects and goes to Sapporo to teach at a girls academy. However, that girls academy is not typical—it is on board the Amanohara, and the five girls Shintaro teaches are known as the Raimu Unit—girls with the ability to summon powerful beings to fight for them. Shintaro eventually becomes their teacher and general in battle, and so the six embark on a weird and excessively erotic journey, as Shintaro helps the girls overcome their weaknesses, become stronger for the final stand at Lushun, and also understand the motives of the "Russian Spiritual Corps" that assist the opponent, which, unfortunately, has one member whom Shintaro knew well...

After battle in first season battleship Amanohara was serious damaged and need to repair. It land on island where a Gogyou festival just begin. Umakai Shintaro and his five girls student who know as Raimu Unit begin enjoy a peace time in that island. But the enemy still follow them around. How Umakai Shintaro and his five girls student fight against the enemy. Still his five girls student begin try to draw his attention into them.