Darklight — Jill Myles

When Rose Hawthorne accepts the task that her fairy godmother sets upon her, it seems straightforward enough: steal a flower from the underworld. Not such a hard task for someone that's acting as a stand-in for the Goddess of Spring. There's just one tiny problem â€" fate seems destined to hurl her through the legend of Persephone.

Now, she's been kidnapped by an all-too seductive dark god who wants to teach her all the exquisite ways of passion…and Rose wants more than anything to be his willing pupil. But to stay in this world with Hades, she must complete the fairy godmother's task. And completing it will force her to betray the man she desperately wants to belong to.

This novella (21,000 words) features a naughty pretend-goddess, a naughtier god, and just a dash of voyeurism.