REBORN! Season 4 Episode 89 Piano of Sorrow

After an explanation of the mystery of the boxes and theories concerning them, Tsuna, Yamamoto, and Gokudera's training becomes standardized. Their training is difficult and they are exhausted every day. Of the three of them, Gokudera isn't doing very well. Day by day, he takes his own actions. Tsuna is worried that there's something wrong with him. Reborn tells him about Gokudera's past… Meanwhile, the Millefiore's Glo Xinia is headed to Japan.