September 23rd.

On that day, when Shinozaki Ichiya celebrated his 17th birthday, a single email message arrived.

"Happy Birthday."

"Your fate is changing,"
"and just this once I give you a small gift, your freedom."

The name of the sender was "Unknown".
Of course there was no clue as to who sent it, that night.

But just after receiving that prank message, "Their" reality began to change.

The youths hiding the secret,
of who really sent the message.

And on that night they stepped into reality.
To start "That day" over again, and again, to change it completely.

[From Aarinfantasy Forums]