Sachiko and Masato Azuma have overcome numerous obstacles in dealing with their firstborn son Hikaru's autism. Having saved their marriage from ending in ruins, the young couple has welcomed a healthy baby girl, Kanon, into their tight-knit family. But with the obvious differences between Hikaru's and Kanon's developmental abilities, it becomes apparent that social prejudices against Hikaru's disability are never far away. As Hikaru moves into fourth grade, Sachiko encounters a new student, Miyu, whose mother has completely given up on her daughter's life and her own. With the help of Hikaru's beloved teacher, Aoki-sensei, Sachiko aims to bring hope back to Miyu's family. But when Aoki-sensei transfers to a different school and Hikaru's special education class is thrown into upheaval by yet another tragedy, can Sachiko continue to hold on to her own hope for her son's future?