A working-class girl and her trust-fund boyfriend move into a downtown New York tenement apartment to try to make a life together. Their volatile relationship is further complicated when they learn their angry downstairs neighbor is building an A-bomb in his apartment.

Robert McCall is a former agent of a secret government agency who is now running his own private crime fighting operation where he fashions himself as "The Equalizer." It is a service for victims of the system who have exhausted all possible means of seeking justice and have nowhere to go. McCall promises to even out the odds for them.

The true story of Leonard Matlovich, a U.S. Air Force sergeant who, in 1975, publicly divulged his homosexuality and fought to remain in service.