Takamiya Haruto, a university student, is requested by his older sister to help out at the company she works in. When he gets there, he learns something astonishing: The company his sister works at — It's an eroge company!

His sister was among the staff of Ramune soft, an eroge studio.
Their latest production almost complete, they're so busy they'd even take cat's helping hand. Even though he has zero knowledge; Haruto accepts, unable to decline, and begins working at Ramune soft.

But, surprisingly...
Ramune soft's staff were all women.
Surrounded by charming women who passionately work on eroge, can Haruto experience wonderful romance like in a game (=eroge)?

[Translated from DLsite]