When a depressed young man goes to bed alone on Christmas Eve, he finds himself awoken in the night by a succubus. The even stranger part is that she claims to be working on behalf of Christmas itself, and that she's here to grant a wish the protagonist made long ago:
To be a girl
Will he be able to prevent the demonic seductress from turning him into a woman before the night is through? And why does the thought of that fill him with such weird fuzzy feelings?