A {Black Butler}

"Don't take it personally. It's just business."

There is a professional murderer on the loose and Ciel Phantomhive has to find out who it is. But this murderer was different. He left no trace except for notes with the letter "A". The Queen was getting worried and so The Queen's Guard Dog was on the case.

But to catch a murderer, you need to play the game right to find the mastermind

With a murderer like "A", you need to play it with the mastermind.

{Ciel Phantomhive One-Shot}