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 bastard, don't think you've won...
Bastardo, ¡no creas que has ganado solo porque tienes novia!
Imbécil, ¡no creas que has ganado porque tengas novia!
Maldito, você acha que venceu