Mathieu, 19, is a reserved young man with no real close friends who works at a slaughterhouse in rural Québec. His daily routine is upended with an unexpected call from his free-spirited older sister Heidi, who left for the United States three years earlier, who asks him to drive down to Arizona and bring her back home. Her call for help takes him on an unfamiliar journey that reopens old family wounds from growing up in foster care, putting their reunion to the test. The Mechanics of Borders is a road movie that explores the complexity of rebuilding bonds within broken families.