Nick is, let's not beat around the bush, a loser. A shitty job, mediocre apartment, a total lack of facial hair, and perpetual virginity. So, when one day he finds a magical tome, he decides to turn his life around and summon a succubus.
The succubus is more than happy to enter his life completely, and give him what she calls the "girlfriend experience". The only problem for Nick is... he probably had a different idea what that means than her.