"Let's meet at the place where it all began." The true plot is revealed as Takuru travels to the Hikariwo. There he eets the other person behind the series of brutal killings.  But a deeper mystery lurks in the background: what Serika is telling him doesn't make sense, and he's convinced that as horrible as the story is, there's more to it than even he knows.
Whatever you do,
make sure you don't regret it.
مهما فعلت، احرص على ألّا تتحسّر على فعلتك
Bereue bloß keine Entscheidung,
die du getroffen hast.
Asegúrate de no arrepentirte de nada.
Procura no arrepentirte de nada.
Fais en sorte
de n’avoir aucun regret.
Cerca per lo meno di non aver rimpianti.
Seja lá o que fizer, faça 
questão de não se arrepender.