Seventeen-year-old Xochi is alone in San Francisco, running from her painful past: the mother who abandoned her, the man who betrayed her. Then one day, she meets Pallas, a precocious twelve-year-old who lives with her rockstar family in one of the city's storybook Victorians. Xochi accepts a position as Pallas's live-in governess and quickly finds her place in the girl's tight-knit household, which operates on a free-love philosophy and easy warmth despite the band's growing fame.

But on the night of the Vernal Equinox, as a concert afterparty rages in the house below, Xochi and Pallas perform a riot-grrrl ritual in good fun, accidentally summoning a pair of ancient beings bound to avenge the wrongs of Xochi's past. She would do anything to preserve her new life, but with the creatures determined to exact vengeance on those who've hurt her, no one is safe--not the family Xochi's chosen, nor the one she left behind.