Follows John McNamara, an FDNY firefighter who was a first responder on 9/11. After being diagnosed with cancer linked to toxins at Ground Zero, he fought to raise awareness about the plight of fellow first responders before his death.

Johnny Mac follows the life of an unsung hero and FDNY Firefighter, John McNamara. John was the quintessential best friend, a loving husband, and a devoted firefighter. He was a first responder on 9/11 and spent 500 plus hours at Ground Zero clearing the rubble. He was eventually diagnosed with stage four cancer and was among the first to link his cancer with the toxins he was exposed to at Ground Zero. Before his death, he fought tirelessly to bring awareness to the plight of his fellow first responders.