Babe and Bobby Wesson have been married for years and their sex life has become a bit dull. Babe is sensuously beautiful, but ashamed of her desires and over the years has become a Valley of the Dolls-type neurotic who refuses her husband sex. One night, she is awakened in the middle of the night by strange noises. Creeping downstairs, she peeks through the outdoor window into her husband's basement garage (where he keeps an extremely valuable vintage Cadillac he believes was once owned by Elvis). Expecting to find Bobby tinkering with his machines, she is shocked to instead find him with a strange woman, who passively gives him a blow job and then lies nearly lifeless as he penetrates her. Shocked, betrayed, and highly aroused, Babe creeps back upstairs and pretends to be asleep when Bobby returns to bed.
The next day Bobby is a bit exhausted but glowing with satisfaction about his new "mistress," Carmen, a blowup doll. Loath to cheat on his possibly-frigid wife, he believes he's found the perfect solution. Imagine Bobby's surprise when he returns home to find Babe, naked and sated in the arms of none other than Carmen! Bobby's secret becomes Babe's compulsion as she finds her sexuality suddenly wide awake; like Lottie (Cameron Diaz) in Being John Malkovich, she discovers her true sexual calling in one scene in using her husband as a sort of human sexual surrogate to make love to the doll she has fallen for. In another scene Babe goes to the mall to buy Carmen sexy underthings and to find a man to service her. Meanwhile nosy neighbor Shirley Gordon keeps pestering Babe, who has been staying home from work to be with Carmen.
When Shirley Gordon's son comes knocking to return a borrowed axe, with which he has accidentally cut himself, she and Carmen together seduce the young boy. Babe and Bobby decide they have to dispose of Carmen, and drive her away to dump her by the roadside. They are pursued by Shirley Gordon, spin off the road and crash into a tree and both are killed. The novel closes with the final sexual fantasies of Bobby and Babe as their bodies slide into the incinerator at the crematorium, while Shirley Gordon drives away with her son and her prize from the accident-Carmen, who, like Stephen King's Christine, has no intention of going away.