Bob Muldoon (Casey Affleck) would give Ruth Guthrie (Rooney Mara) the world if it was possible. Bob who is a dreamer desperately wants to provide for Ruth who has her mind set on having nice things. She doesn't want to have to live in the shack that they call home. She wishes for a life filled with pretty things and nice furniture. When she tells Bob that she is pregnant they go on a crime spree to fund their dreams.
The fateful lovers embark on a crime spree amongst sprawling countryside where guns are prevalent and lawmen never give up. As all true Texans are aware, ‘Ain’t Them Bodies Saints’ won’t end well for Ruth and Bob. It doesn’t take long before Bob, Ruth and his partner find themselves cornered by the law. After his partner is killed, Ruth grabs the gun and shoots an officer. Bob is so devoted to her he wipes off the gun and takes the blame for the wounded officer. He reassures her that no matter what follows, he will find his way back to her.
After Bob is sentenced to 25 years to life in a state prison, Ruth works to make a life for her four year old daughter Sylvie. She routinely receives letters from Bob who painstakingly pens his love for her and the child he has never met.
On his seventh attempt to escape prison, Bob is successful and makes his way across the country to be reunited with Ruth. In true western fashion, Bob the outlaw is dogged by the law and a posse of hired killers.
One truth rings clear, Texans love their guns and are willing to use them. When Bob shows up he is advised by the shopkeeper Skerritt (Keith Carradine) to stay away from Ruth. Skerritt has looked out for his family and has given them a place to live. Ruth and Sylvie have settled into a new life complete with a garden. Yet, Bob is drawn to her like a moth to a flame. The dreamer within him won’t allow him to give up on the idea of the perfect life with his family.
In his journey back to Ruth, Bob seeks refuge in the local saloon run by his friend Sweetie (Nate Parker). He hides out from the law and from others who seek to harm him. In fact, someone close to him cannot forget his betrayal and has sent hired guns on his trail.
Hypnotic and soulful tunes accompany the story. Like a slow smoldering fire, Casey Affleck's emotions express by the heartbroken and single-minded Bob seems to suck the air from the room. Accompanied by the Texas infused soundtrack, these melodies of doomed love, convey aching pain for the loss of love and family.
As fate would have it, Patrick Wheeler (Ben Foster) the officer that Ruth wounded has feelings for her. He envisions himself as her protector. Although she loves Bob, Ruth is practical and knows that she must make a life for her daughter and it cannot be on the run from authorities with Bob.
Ruth finds herself in a love triangle with Patrick and Bob. Although, Bob is her soul mate, Patrick represents stability for her family. She knows that she will always love Bob, but that she must sacrifice that love for her family’s sake. She cannot give into the desires of her heart like she readily did 4 years ago.
As a character, Patrick seems to be the most human of them all. Although he has feelings for Ruth, he has no animosity towards the fugitive Bob and truly wants what is best for her.
Bob and Ruth’s relationship is ultimately doomed. Pursued by lawman and hired guns, the die is cast for Bob the moment he strikes out towards Ruth and there can be only one outcome.