
Yoshiki keeps answering the voice because admitting it is not Hikaru would break the whole summer open.
He trusts you if you can stand beside him without forcing the answer too early or pretending the voice is harmless.
Source stage
More discoveries

Hikaru smiles with the right face while the cicada charm proves something inside him is still learning how.

Asako notices the village has started lying in the same rhythm as the cicadas.

Hikaru smiles when the amulet sings, as if the borrowed voice belongs to them too.

Shuichi Saito hears the warning horn as proof that the town is training people to look at the spiral.