On a certain boring day...
You wake up to find two succubi in front of you.

One of the succubi looks premature, and the other like a servant.
A succubus that wants to grow, and a succubus to help that growth.

The growth of succubus is to become "the ideal queen of a male human."
What she will need is love, education, and of course sex.

'You' are selected as a human representative to help the succubus grow.
You will now live with a 'pure and innocent succubus.'

Give her spirit through naughty things and help her grow into a queen.
A mysterious growing life with a charming succubus begins.

[From DLsite English]