Detectives These Days Are Crazy!

There was once a brilliant detective who built an incredible record of solved cases and enjoyed overwhelming fame.
No mystery could stump him. Every case was wrapped up instantly.
That legendary high school detective was Keiichiro Nagumo.
But that was more than ten years ago.
Now he is plagued by back pain, farsightedness, and sensitive teeth.
He barely understands smartphones, and modern slang like "JK (=high school girl)" leaves him confused. The once-glittering teen detective has become a middle-aged man completely left behind by the times.

"I have not lost my talent... I have simply lost a bit of youth."
One day, a lively high school girl named Mashiro barges into the Nagumo Detective Agency, insisting she wants to become his assistant.
Apparently, she dreams of becoming a detective herself.
And so begins the heart‑pounding daily life of a middle‑aged detective and his quirky, self‑proclaimed pretty JK assistant.