Frank Black, an ex-FBI agent, retires to Seattle to spend more time with his family. Plagued with a gift to see into the minds of killers and psycopaths, Frank joins the mysterious Millennium Group in an attempt to protect his family from the horrors of society that proliferate as the new millennium draws near. But the origins and true purpose of the Group are unclear, and it may not be just society's ills that Frank has to look out for.
As the "new" Ed Cuffle continues to amass victims, Frank is now being falsely held responsible for the death of Barry Baldwin. Emma accepts full membership in the Millennium Group, in exchange for a cure for her father. The FBI fires Frank, leading him to confront both Emma and Peter Watts. Everything will come to a head by the end of this episode, the series finale.