ef - a tale of memories - 2x06 - Season 2, Episode 6- Followmy.tv

In the past, Yu finally comes to terms with his love for Yuko, but must turn down Nagi first. After Kuze plays his violin for Yu and Yuko, Yuko starts crying because the music is so beautiful and runs out of the room; Yu chases after her to the school roof. There, Yu professes full devotion to Yuko, and she finally reveals to him what she has been hiding this whole time. Her older adoptive brother has been physically abusing Yuko for years, and she infers that this could have all been avoided had Yu merely said he wanted a younger sister back when they were at the orphanage together.