Yuuga Maejima, a detective who works in the Special Investigation Office of the Metropolitan Police Department's Criminal Investigation Department, is a hardcore stamp enthusiast. He is a carefree civil servant who is neither smart nor passionate about his work.
After all, he is only interested in stamps!!
…But his passion for stamps sometimes helps him solve difficult cases…!!

Stamps are mirrors that reflect the times and culture.
Even in today's world of e-mails,
stamps and postmarks can be clues in tracking down criminals!!