Ai, Sunakawa's sister three years his senior, is shocked to learn during a home visit that Takeo is dating. Having secretly harbored feelings of her own for Takeo, Ai is suspicious of Takeo's girlfriend and launches her own investigation...
It could be that she's two-timing you, 
having an affair,
Etwa dass sie eine Affäre hat …
Puede que te esté engañando, 
esté teniendo una aventura
Puede que te esté engañando, 
esté teniendo una aventura
Peut-être qu’elle te trompe,
Forse sta facendo il doppio gioco, o ti tradisce,
Ela pode ter outro namorado ou um caso.