"It's summer. The place is a crater lake near the naturally ambient, rural village "Takachiho". The protagonist is standing still, blankly looking at the far-away sky.

Amnesia...
His memories of the past have been lost.
It's a strange thought, but to him on that day, the sky seems tailored to both dusk and sunrise, a mysterious color..."

The protagonist, Aisa Ryu was a freeloader in a house, living there with four beautiful sisters. Until suddenly, one day, a sad incident occurred...

[Translated from Official Site]