Hanako's revelation that she's writing an article about Hisao's science club for the next school newspaper in an attempt to get him a few more members. It's a very sweet gesture that shows how serious Hanako is in wanting to support Hisao.
Lilly's and Hanako's reconciliation. Not only do they fix their damaged friendship, but Hanako gets an opportunity to emotionally support Lilly during her time of need. Lilly ends the phone call with her mother by reassuring her that she'll be okay in Japan, even without Akira, since she has someone who is as much a sister to her as Akira is.
The final moment of the story. Hanako, as a gesture of renewed trust in her friend, allows Lilly to feel her face...even the burned side. Lilly is overjoyed to finally know what Hanako looks like.