33 parts Complete Hatsune Miku, also known as Assassin: Songbird, was suddenly given a mission to protect a pair of twins from a rich family. Keep them away from harm, make sure no one gets to them, seems like a bodyguard's job. She had started doing this for the pay, but what happens when you become friends with them, or even fall in love with one of them?
The twins, Kagamine Rin and Len, on the other hand, couldn't understand why they needed a new bodyguard. What was so different about her? What makes her different from the other bodyguards they had? Most importantly, what were their parents hiding from them, why were they always away?
Secrets are being released. Love is lost and found. Would it be a happy ending for everyone?