A subway explosion leads to an influx of patients at The Knick, but little margin for profit. Pursued by Henry, Lucy takes to heart advice from one of Ping Wu's girls. An addict's misfortune gives Thackery an ideal test case for his latest theory on addiction. Bertie submits his adrenalin research to Zinberg. Cornelia gets a new clue in Speight's death. Barrow repays a debt but gets no credit. Genevieve charms the Chickerings. Harriet finds herself a boarding-house pariah.
The setting: downtown New York in 1900, a tumultuous time of massive change and great progress. The series centers around the groundbreaking surgeons, nurses and staff at Knickerbocker Hospital, who are pushing the bounds of medicine in a time of astonishingly high mortality rates and zero antibiotics.