There's an Onmyoji in Yokohama

The Armed Detective Agency receives a request from a client who wants them to help find his missing younger brother.

The agency members look at the photo of a child with black-and-white hair and geometric shapes in his eyes, then slowly type out a "?".

Then they look up at the client.

He's wearing a black short jacket, its frog closures oddly resembling two fish, one black and one white, joined together. Yumeno Haruya has a pentagram in his blue right eye and an eerie red eye on the left. His black-and-white hair is neatly parted down the middle.

No matter how you look at it, he seems to be related to Q by blood...

So here's the question: why hasn't the Port Mafia found this person?

After four years studying abroad, Yumeno Haruya returns home to discover that his younger brother has disappeared.

Desperate to find out where his brother went, Yumeno Haruya has no choice but to hire the Armed Detective Agency. He learns that his brother is being held by the Port Mafia.

How can he allow that?

Midnight.

The night beyond the window is hazy, and a blood moon slowly rises.

The boundary between yin and yang fades away.

...It's the perfect time to bring his brother home.

Theme: A yin-yang master must bring his younger brother home.