Underbelly is a crime drama set in the 1000 Islands region, home to a picturesque river that serves as a border between Canada and the U.S. Officer Henry Roland finds evidence linking a case of missing illegal substances to his childhood best friend, Tommy Hawley. As Henry embarks on a mission to save his friend, a ruthless British crime family, led by matriarch May Ferguson, is also looking for the missing contraband and Tommy.