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...
Only a woman would understand 
another woman's true nature!
Nur eine Frau kann die Absichten
einer Frau durchschauen!
¡Solo una mujer entiende la 
verdadera naturaleza de otra mujer!
¡Solo una mujer entiende la 
verdadera naturaleza de otra mujer!
Seule une femme peut comprendre 
la vraie nature d’une femme !
Solo una donna può capire
la vera natura di un'altra donna!
Só uma mulher é capaz de entender 
bem a verdadeira natureza de outra!