The story focuses on Nicole Gunther-Perrin, a young lawyer in late 20th-century Los Angeles who is dissatisfied with her hectic life, which includes balancing her career with being a mother and dealing with her deadbeat ex-husband and sexist coworkers.

Believing the past to be a better time, one evening after a particularly distressing day, she makes a wistful plea to a plaque of two Roman gods, Liber and Libera, who take it as a prayer.

Unknown to her, the plaque, which she thinks is a tourist copy picked up in Europe on holidays on a trip a few years earlier, is actually an ancient relic from the Roman Era.

In general, she finds out the hard way that life in the past was not quite what she thought it would be: slavery is taken for granted, and there are no women's rights, no effective medicine or clean medical practices, little entertainment, and no tampons.

Jo Walton remarked Household Gods is a well-written book that always annoys the heck out of me.... Nicole Gunther-Perrin is a lawyer in Los Angeles, and she's the most irritating person you could ever spend a whole book with.... she's had this marvellous opportunity and there she is so passive and ignorant that I want to kick her out of the way and do it myself and prove that women can be Martin Padway and not all Nicole Gunther-Perrin.