It is 1860, and slavery is tearing the nation apart. In the rough-hewn Third Ward of Milwaukee, the law is treated casually by the mostly Irish immigrants who live there and by those charged with enforcing it. People are safe enough by day, yet trouble brews beneath the surface. As the Lady Elgin, a luxury paddleboat steamer, docks at the waterfront, Irish immigrants are preparing to secretly set into motion a plan that will put them on a collision course with history and forever alter the political and ethnic makeup of their city.

Wisconsin is divided politically. With the Democrats splitting and the South recruiting its own candidates, the members of Milwaukee's Union Guard, led by Captain Garrett Barry, decide to attend a political rally for Lincoln's opponent, Stephen Douglas.

As the fear of war hangs in the air, hundreds of Irish men, women, and their children board the Lady Elgin for Chicago, unaware that their journey is about to take a tragic turn.

In this compelling tale based on true events, Irish mythology and American history are interwoven into an unforgettable story of intrigue and heartbreak that provides a glimpse into the lives of those lost on a September night in 1860 in the greatest maritime disaster on open water in the history of the Great Lakes.