Daichi, as a policeman, has been given an assignment to talk to the principal of a local grade school after they had been getting security threats. He walks into the school, noticing how the halls are basically empty, presumably because all the kids are in class, until he sees a teacher walk out from the staff room

“Suga?!”

Daichi exclaims as he sees Suga walk out of the staff room, having not seen him in like 6 years, since they graduated.