Blood+ is the TV series continuation of the story that started with Blood: The Last Vampire. The story continues the ongoing secret war between humanity and the immortal Vampiric monsters known as Chiropterans. These creatures are capable of disguising themselves as human beings in order to attack their victims.
The war has extended into modern times and the latest resistance force is a secret organization called "Red Shield," which is a group that dedicates itself to eradicating the Chiropteran threat.
Saya Otanashi is a seemingly normal young High School student living peacefully with her family. However, she has no memory of her past. In time, Saya will learn (the hard way) of her vital role in this secret war.