Early in The Sweetness, an inquisitive young girl asks her grandmother why she is carrying nothing but a jug of sliced lemons and water when they are forced by the Germans to evacuate their ghetto. "Something sour to remind me of the sweetness," she tells her, setting the theme for what they must remember to survive. Set during World War II, the novel is the parallel tale of two Jewish girls, cousins, living on separate continents, whose strikingly different lives ultimately converge.

Brooklyn-born Mira Kane is the 18-year-old daughter of a well-to-do manufacturer of women's knitwear in New York. Her cousin, eight-year-old Rosha Kaninsky, is the lone survivor of a family in Vilna exterminated by the invading Nazis. But unbeknownst to her American relatives, Rosha did not perish. Desperate to save his only child during a roundup of their ghetto, her father thrusts her into the arms of a Polish Catholic candlemaker, who then hides her in a root cellar - putting her own family at risk. The headstrong and talented Mira, who dreams of escaping Brooklyn for a career as a fashion designer, finds her ambitions abruptly thwarted when, traumatized at the fate of his European relatives, her father becomes intent on safeguarding his loved ones from threats of a brutal world, and all the family must challenge his unuttered but injurious survivor guilt. Though the American Kanes endure the experience of the Jews who got out, they reveal how even in the safety of our lives, we are profoundly affected by the dire circumstances of others.