Husband and wife Thornton and Rutha Blackburn, enslaved African-Americans, escaped Kentucky in 1831, when they learned Rutha was being sold to a plantation in the South. They settled in the free city of Detroit but were discovered and captured by slave catchers in 1833.

On June 16, two Black women manage to smuggle Rutha out of jail and over the river to freedom in Canada. The next day, an armed group of 40 to 400 Black Detroiters gather outside the jail and demand the release of Thornton. They scuffle with the police, chaos erupts, and the sheriff is fatally injured. In the confusion, Thornton is freed and joins Rutha Canada.

Outraged white mobs assault Black people on the streets and burn over 40 Black homes and businesses. Violence continues into July when martial law is declared.