In 1868, Maryland's embryonic maritime law enforcement agency, the State Oyster Police, set out on its mission to enforce the state's laws on the Chesapeake Bay. Haynie McKenna, the agency's deputy commander, serves as captain of the steamer "Leila." With a crew of untested officers, he heads to the Honga River in search of a rogue waterman, Marrok Blanchard, and his sons.