Em 1873, uma pequena cidade do Texas é atacada por uma gangue de malfeitores sedentos por sangue. Um misterioso pistoleiro russo se junta ao delegado e ao xerife local na tentativa de proteger a cidade e os seus habitantes.

Travers, a doctor who deserted his military post, searches the frontier for the wife who left him. His quest is thrown off course when he saves Sarah, a woman left for dead after a wagon raid. With the cavalry, the law, and deranged outlaws on their trail, Sarah and Travers set off together to find this missing woman. Heart of the Gun is a psychological thriller and a romance drama wrapped in a gritty Western setting.

Part of 12 Western Feature Films which will be produced in 12 Months during 2020: When an outlaw is captured and scheduled to hang, the wife of the local deputy makes a decision that will forever change her life. Mabel is in love with the arrested man. Will she remain loyal to her husband Jonathan or follow her heart?