A young woman approaches the Boy Detectives' Club and asks them to find the intended recipient of a series of threat letters her boyfriend made. They accept the job and begin to tail her boyfriend. Meanwhile Kobayashi, after missing his chance to return Hanasaki's dropped wallet, uses it to buy a desperately needed meal. Hanasaki finds out by checking his electronic money usage history, and he convinces Kobayashi to join him on the current investigation in a second attempt to get him to join the club...
go out with a guy who works at a 
place that uses cheap oil like this?
mit einem Typen ausgehen,
der so billiges Öl benutzt?
saldría con un tipo que trabaja
en un lugar que usa este aceite barato?
sairia com um cara que trabalha
onde usa óleo barato?