As a medical emergency temporarily sidelines Laurie, impulsive Aria turns to a controversial new technique: using genealogic DNA databases to track down those who don't want to be found. Working with experts at a start-up ancestry website, she plans to trace the fetus's DNA back to likely male relatives in the hopes of identifying the mystery father. But when Kera's closest friend and fellow social worker is murdered, the need for answers becomes even more urgent. Because someone out there clearly doesn't want Kera's secrets to come to light . . . and if Aria gets any closer to the truth, she and Laurie might find themselves a killer's next targets.