Twenty-three years ago, Maggie D'arcy's family received a call from the Dublin police. Her cousin Erin has been missing for several days. Maggie herself spent weeks in Ireland, trying to track Erin's movements, working beside the police. But it was to no avail: no trace of her was ever found.

The experience inspired Maggie to become a cop. Now, back on Long Island, more than 20 years have passed. Maggie is a detective and a divorced mother of a teenager. When the Gardai call to say that Erin's scarf has been found and another young woman has gone missing, Maggie returns to Ireland, awakening all the complicated feelings from the first trip. The despair and frustration of not knowing what happened to Erin. Her attraction to Erin's coworker, now a professor, who never fully explained their relationship. And her determination to solve the case, once and for all.