Shun's younger brother Fuyuki and his girlfriend Mamiya-san kissed.  When Shun finds out, he asks his friends what he should do as Fuyuki's older brother.
Fuyuki ignores his brother and goes on a date with Mamiya.  The gang decides to follow the couple on their date and end up at a karaoke box.
You've become a fully-fledged 
pervert over one little kiss.
Te has convertido en un completo pervertido por un simple beso.
Te has convertido en un completo pervertido por un simple beso.
Você virou um tarado completo
 só com um beijinho.