Naho got into a fight with Kakeru on New Year's Eve, and never managed to apologize to him before he passed away. At least, that's what the letter from the future says. However, Naho now believes that she's capable of dealing with whatever may come up, and faces New Year's Eve head-on.
I was the only one who knew
...كنت أنا الوحيد من يعرف
Ich habe als Einziger erfahren,
Yo era el único que sabía
lo que sentían ambos.
Yo era el único que sabía
lo que sentían los dos.
J’étais le seul à connaître 
les sentiments…
Ero l'unico a sapere
cosa provavano sia Naho che Kakeru.
Eu era o único que sabia dos 
sentimentos da Naho e do Kakeru.
Я единственный знал