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.
As a fellow man, I'm starting 
to worry about you, Shun.
Como otro hombre, comienzo a preocuparme por ti, Shun.
Como otro hombre, comienzo a preocuparme por ti, Shun.
Como companheiro homem, começo
 a me preocupar com você, Shun.