Thackery enlists Edwards to help him test a new hypothesis. After rejecting Robertson's advances at The Knick, Lucy learns that confession isn't always good for the soul. Young journalist Genevieve Everidge works on a story about one of Thackery's rivals. Cornelia is dismayed by the limits of her husband's (Tom Lipinksi) sympathies; Barrow faces a new adversary at Tammany Hall; Gallinger is intrigued by a discussion of eugenics at a class reunion; Edwards deals with a surprise visitor.