A slightly terrible thing has happened...

All of a sudden, an angel and demon girl come uninvited to the protagonist's house. "We've run away!" they exclaim, and are looking for any place to stay. And they can stay here, on the condition that they do absolutely anything requested.
Explore the bodies and hearts of angel Yuuna and devil Aika; two girls you can treat with violence or love.

[from DLsite English]