"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.
I would observe it, calculate it,
come up with a theory,
كنتُ سأراقب ذلك وأجري حساباتي وأخرج بنظريّة
Ich würde das beobachten,
Observarlo, formar teorías
y experimentar de nuevo.
Observarlo, formar teorías
y experimentar de nuevo.
Il fallait observer,
faire des calculs, les analyser,
Eu observaria isso, faria 
cálculos, pensaria numa teoria,