The scene where Nana and Hachiko go to Trapnest's concert in Hachiko's hometown, and Nana sees Ren for the first time in two years. It doesn't help that the song Trapnest performed was the extremely touching "A little pain", either.
When Hachiko saw Shouji hugging Sachiko. Hachiko was so shocked that she refused to fight for Shouji, and broke up with him.
Another tearjerker scene was when Hachiko broke up with Nobu because she got pregnant and decided that Takumi was the better choice since he would be able to support the child without any trouble. She also thought that she was in love with Takumi.
Yasu going with Misato to Nana's hotel to tell her the news. And she was so happy somebody came for her, too.