In her eighty-fifth year, Fern Halvorsen tells the story of a childhood journey across Lake Michigan and the secret she has kept since that ill-fated voyage. In the brutally cold winter of 1936, Henrik Halvorsen takes his daughter Fern away on his coal-fired ferry, transporting railroad cars across the icy lake. The five-year-old girl revels in the freedom of the vessel, befriending a stowaway cat and a young deckhand. The sighting of a ghost ship, though, presages danger for all aboard.