The Hayami Detective Agency is an unorthodox private investigations agency run by Seiji Hayami.
The Agency is located under a concrete bridge in a cottage that shows Seiji's status of living homeless. Despite this, he has access to internet and electricity as shown when he is able to see news reports on a TV and uses a laptop for research. More than often it is visited by members of the homeless association where they share meals and exchange information. There do not appear to be many clients due to the agency's appearance. Seiji however does have a reputation that gets around and brings some people to his agency.