Oreimo follows the daily life of an ordinary high school boy named Kyousuke Kousaka. Kyousuke’s younger sister Kirino is a pretty fashion model, but also hides a dark secret of being an otaku of adult games. Kyousuke is the only person to whom Kirino reveals her hidden obsession and other issues.

Vampires exist. It is the duty of Hellsing, an organization sponsored by the British government, to hide that frightening fact and protect the blissfully unaware populace. Lately, vampire activity has been on the rise and the cause is more alarming than anything they could have imagined.

In the big city of Yanagihara, the masses of people and buildings make it a bustling place to exist, and yet, people will meet and fall in love here in this city.