Remember the date that Ken & Miyuki had back in File 3, "Love's Highway Stars"? Well, they haven't gone out together again since then; in fact Yoriko & Aoi (Now patrol partners) are discussing it while on patrol when they spot Ken at a smoke shop talking to an attractive girl. His bringing cakes to her & asking about her father (All overheard remotely by Yoriko, Natsumi & Miyuki via a parabolic microphone later) doesn't make the picture any better, especially the next day when Miyuki & Natsumi spot the two riding together on Ken's bike. But no worries-The girl's father owns the smoke shop & is a fancier of vintage auto parts who happens to own a Toyota tachometer that Miyuki's been wanting for some time. It would make a great birthday surprise for Miyuki if Ken could get it, wouldn't it?
Two flashbacks in this episode help give a little continuity from the OVA series: 1) Miyuki referred to the work she put into fixing Ken's bike back in File 1 & that is recalled here & 2) the key charm that Ken gave her on their date in File 3. As for Natsumi, well...So many lunches & so little time (For the Chief & Detective Tokuno, that is)...
BTW, that old lady on the scooter makes another appearance! Who is this lady & why does she always seem to be in hurry? We'll all find out about her next time in File 10, "The Outlaw Scooter Mama".