At forty-three, Christina Lennox thought her future was settled: marriage to Ed, children, a house of their own. But this is not that future: her marriage has ended, fractured by the stress of five rounds of IVF and two miscarriages. Overwhelmed by grief and disappointment, Ed has relocated to San Francisco and Christina's dream of becoming a mother rests on persuading him to let her go ahead with one final round of IVF, using the last frozen embryo they have stored at the clinic.