Dive in the Vampire Bund Vol 1

The Vampire Bund, a peaceful island nation of vampires off the coast of Tokyo and ruled by Princess Mina Tepes, has seen its share of conflict and turmoil. Yet there are times of relative tranquility when the Bund is a popular tourist destination. When two teenage tourists visit the Bund and are unexpectedly turned into vampires, they appeal to Mina and her loyal lycanthrope bodyguard, Akira, for help. Their only hope is to find a cure to reverse their vampirism within forty-eight hours, or they will be stuck as vampires forever. Unfortunately for them, their race against time turns into a game of cat and mouse that takes them across the entire Bund in pursuit of the one person who holds the key to their salvation.

Source: Anime News Network Encyclopedia