One summer day, in gentle rain...
Yuuna Hibiki saw two girls kiss lips tenderly.
One young girl with green hair, Mai Himeno.
Yuuna's rival.
The other, Chisa Hayase.
Yuuna's true love.

To see her heart's desire kissing another...
That scene shocked Yuuna.
But she was powerless to change it.
Because she is not a being of this world.
Yuuna is an ethereal spirit left behind to exist in Earth,
seeing Chisa longingly and wanting to be thought of by her.
But, that remains a distant prayer.

It is in this state that Iori Senzaki discovers Yuuna.
She is an academic and an eccentric, and can see such things.
Together they will find a way to achieve Yuuna's dream...

[From DLsite English]