You play as an angel-in-training.
Your last job before becoming a fully-fledged seraph is to watch over a girl named Yurume Omata.
Well this'll be a piece of cake! Or not. Yurume is kind of dumb, and her sense of virtue is weak, to say the least. If a guy tries to pick her up on the street, she'll just go with it. She lets people grope her on the train without any refusal, and she's just generally a dope when it comes to being aware of her own body.
Borrowing the powers of a senior angel named Kuro, you're going to try to find out how to guide Yurume to a happy life. As an angel, however, you cannot be seen or heard by your young ward. That makes it especially hard to guide her in any meaningful way...
Without your help, she just keeps on finding herself in sexy situations!