A cartographer by profession, Claire's mapping of her sister's travels moves her not only through Rachel's increasingly desperate search for relief from her migraines but also through their shared past. Most interestingly, this mapping of the past also moves Claire into a future that is more hers than the earlier parts of her life. Bush makes the missing-person mystery compelling enough to make the subtle shift in focus to Claire's developmental journey surprising and satisfying.

This well-written novel offers a fascinating inside look at the experience of migraine in its dailiness as well as over time. Bush explains medical theories of migraine clearly in the context of the plot, as well as offering an interesting sense of migraine culture, for example, various types of "cure lore," including anecdotes about the lengths to which migraineurs will go to relieve their suffering. She offers to the non-migraineur a picture of how migraine can shape daily life, inflect relationships, and complicate decisions about parenthood.

Bush artfully interweaves Rachel's disappearance with the clinical and experiential mysteries of migraine management and the universal one of family relationships, so that with each chapter, Claire is getting closer to Rachel, deciphering something about their parents and the siblings' relationships, and becoming more adventurously herself. Claire's story expands both beyond migraine and meaningfully through it. Of specific interest for its focus on migraine, the novel's themes can also be extrapolated to other chronic illnesses and disabilities.