Don't read this for the world-building or thrilling sci-fi suspense. There is none. The plot IS the romance and the zombies are a just a stinky, moaning distraction from the MFM hanky-panky. In fact, the overall tone is light and playful. Despite the abundance of flirting and sex, it's light on the menage and not infected by vulgarity. Add to that imaginative writing, and you've got a wild cocktail of erotic, gory fun.