Over four hundred years ago, three sages claimed the pitch-black sacred lake in the Mokegawa region as their own. They made a pact to each take exclusive control of the lake at different times—dawn, noon, and dusk.
The lake’s spirits, inspired by the sages’ wisdom, found a way to purify the dark waters.
But the three sages grew to dislike the now monotonous lake and eventually left, going their separate ways.
Later, to end a war, they set aside their differences and established M University by the lake, nurturing talent and working to rebuild the world.

Over four hundred years later, M-City, built around M University, has become a global leader in technological advancement.
Today, M-City is hosting its annual Open Day, but this year’s event seems far from peaceful…
A research scientist, a literature student, an astronomy student, a chemical company employee, a school staff member, a communications company director, a game programmer, an out-of-town dance student, a wealthy heiress, and an intern reporter all find their daily lives taking an unexpected turn.
On the eve of upheaval, the winds of change blow fiercely.
Their quiet lives are disrupted as a series of sudden events drags them into a sinister conspiracy targeting M-City.
These ten ordinary individuals, who had no prior connection, are now inexplicably linked. Their choices will determine the fate of all of M-City…

[Translated from steam]