I watched the first episode, and I've a theory (already!) I want to test out on the people who've played the game...
Also, where would I go to get the sound novel itself? Amazon.co.jp?
EDIT: might have to go to specialty stores like animate.
Anyway, some introductions to the series ("the same day in June every year for four years") made me think of Shirley Jackson's short story "The Lottery".
If you haven't read it,
please do so, it's one of the greatest American short stories ever.
I went and re-read The Lottery, and guess what? The lottery is every year in June as well!