Futari no Kimochi

Kan Okada, a third year high school student getting ready to take his exams for university, gets reunited with his brother's ex-wife Fuyumi, at his prep school after 3 long years. When coming home one night from playing tennis together, Hiroshi, without thinking, kisses her. What will become of his relationship with his brother, who just so happened to be there to witness it all?

(Source: Beaglee Inc.)