In Kansas City 2044, Joseph "Joe" Simmons successfully "closes his loop" by unknowingly killing his older self sent back in time. He soon discovers eight gold bars tied to the restrained and masked corpse which is his employers' severance pay for the Looper's final job. Knowing it was inevitable that he would have to murder his future doppelganger one day, Joe bitterly realized that he had 30-year-life expectancy before the same thing happened to him. So he took his gold and silver bars and retired to Shanghai, China to live out the rest of his days.
Later Years until 2074
From year 1 to year 6, he lived in luxury, did drugs, partied, etc, until nearly going broke. In year 10, he eventually resorted to killing again to maintain his lifestyle for the next ten years later and had to be dirtier than before by going deeper into a life of crime as not only an assassin, but also a terrorist, hit-man, enforcer; a Gatman, which is a status Loopers acquire when they close their Loops as Joe did years ago. In another ten years Joe is a force to be reckoned with on the streets of Shanghai and becomes a "made man" who has his own enforcers that do the dirty work for him. In year 23, during a fight at a club a woman catches his eye, they fall in love and she changes him into a caring and loving man that causes him to turn away from his life of crime. Soon after, Joe marries and settles down with this woman, then his happiness is put on hold after hearing word of a new and powerful Crime boss, that has a prosthetic jaw and enhanced Telekinetic abilities, dubbed "The Rainmaker", who puts out a contract for all Loops to be closed, including Joe's. Four years later, The Rainmaker's men find and storm Joe's home, accidentally killing Joe's new wife when they come to take him, much to Joe's horror. Instead of going with the gangsters quietly, Joe kills all of the men and sends himself back in time. His intention is to travel back in time to when his Loop was first closed and kill the Rainmaker when he is a child (acting on information he had earlier gotten stating the Rainmaker's age and location 30 years prior) in order to save his wife in the future.
Once again in Kansas 2044, though an alternate timeline, Old Joe reappears however unrestrained and unmasked (as the old Joe he killed was) in front of a younger Joe. Startled, the younger Joe hesitates before firing a shot from his powerful blunderbuss, however Old Joe is able to turn his back to the shot which harmlessly hits the gold he had earlier strapped to himself. While Young Joe frantically tries to reload Old Joe rushes him and knocks the young assassin out cold before setting out to the first address, out of three, that the Rainmaker is currently living at. Later Old Joe meets with his younger self at a diner to explain his mission of retribution and attempt to save his wife, however Young Joe attempts to kill Old Joe that starts a struggle between the two, interrupted when gangsters, including the vile Kid Blue, show up to kill both versions of Joe on orders from Young Joe's boss, Abe. However both Joe's escape the ambush and go their separate ways.
Old Joe then sets out to his first address he has on The Rainmaker, upon finding it he sees his target, a defenseless ten year old boy. Old Joe however acting on his passion to save his wife reluctantly kills the young boy, however when Old Joe's timeline is not set back to before the Rainmaker's attack on him he realizes to his horror he has killed the wrong child. Never the less Old Joe continues on his mission to find the right child, determined to save his wife. As Old Joe hunts the remaining two children, he begins to lose his memory of his wife, as Young Joe has found himself taking refuge on a farm inhabited by a woman named Sarah and her powerful telepathic son, Cid. The longer Young Joe stays and falls for Sarah those memories begin to replace Old Joe's of his wife.
Soon after, Old Joe desperately tracks down the second child and prepares to execute him, however Kid Blue had set a trap for him and captures Old Joe. He is later brought to Abe's strip club where Old Joe breaks free and kills Abe and all of his men with the exception of Kid Blue. Old Joe now realizes that the child he is looking for is in fact the same child that his younger self is now staying with on the farm, due to Young Joe witnessing Cid's Powerful telekinetic abilities and Old Joe inheriting those memories. Once at the farm a tense stand off ensues between the two Joes', where Old Joe attempts to bribe his younger self with all the gold he collected from Abe and his men. As the two exchange words an enraged Kid Blue attacks Young Joe which ends in Blue's death. Old Joe uses this opportunity to track down Sarah and Cid.
Finding them both in a field he attempts shoot Cid but only wounds him in the jaw, hence the prosthesis he needed later in life. Sarah then calms an enraged Cid down after he attempts to kill Old Joe with a telekinetic blast. Old Joe then once again takes aim at Cid who is ordered to run by his mother who then begins to jump in front of Old Joe's gun. Young Joe then happens on the scene just as Old Joe is about to shoot Sarah in front of her son, Young Joe realizes that this event and growing up without the love of his mother, is what will eventually cause Cid to become the violent crime boss known as the Rainmaker. Old Joe could only scream in frustration in the crop fields tearing them up having lost Cid who freight-hopped into a train. With this revelation and Young Joe being too far away to shoot Old Joe with his Blunderbuss, he turns the weapon on himself and shoots himself in the chest, killing him instantly. Old Joe then feels the shot and looks up at Sarah in horror before fading out of existence. Young Joe's act of sacrifice effectively saves Sarah's life and prevents Cid from becoming the Rainmaker. With Young Joe taking his own life, it means Old Joe will never go down the tragic road that life takes him and is redeemed as an indirect result. Plus, despite not killing Cid to prevent him from becoming the Rainmaker, Old Joe still succeeds in his goal as presumably the identity of the Rainmaker is destroyed and thus, never exists in the future. His wife was saved but he did not reunite with her. It's unknown if the present was altered as well, it's safe to assume that since Young Joe erased Old Joe from existance, all the damages that Old Joe cause were possibly undone.