In 1850 the Detroit River was a major track along the Underground Railroad -- the last step to freedom. The journey across the river was dangerous, especially in winter and especially for a 12-year-old boy. When Louis's father left him in charge of the farm he offered his son this advice, "If you don't know what to do, just do what you think I would have done." Louis relies upon his father's words of wisdom when a runaway slave and her two children come looking for safe passage.