Mahiru Shirota prefers the simple life. If it needs done, he'll just do it! But after rescuing a cat he names Kuro, life takes a turn for the complicated. Kuro turns out to be a Servamp - a servant vampire - named Sleepy Ash, and the two form a contract. Kissing his simple life goodbye, Mahiru is pulled into the world of vampires, the seven deadly Servamps, and war. So much for simplicity!