Plot

A woman opts for a cloning procedure after she receives a terminal diagnosis but when she recovers her attempts to have her clone decommissioned fail, leading to a court-mandated duel to the death.

Sarah/Karen Gillan has a mom she avoids and a long distance relationship with Peter. After coughing up blood in her sleep and again at the hospital while waiting to see a doctor, she has tests taken. She's later told that it's an incurable terminal disease - despite feeling fine. As a dying patient, she's offered replacement/cloning. Sarah has a double made at the replacement center as the longer the double spends with Sarah before dying, the more the double will be like Sarah. After 10 months, Sarah's still feeling fine. The doctor tells her that she's had a remission. What about the double? Sarah's problem is that both her boyfriend Peter and her mom get much better along with the double than with Sarah. The law says that there can be only one - and it's decided by a duel to the death. It's time for combat training.—Scott Filtenborg

In the near future, Sarah is a depressed alcoholic in a lackluster relationship with her boyfriend Peter and generally disconnected from her pestering mother. One day, Sarah awakens to find a pool of blood in her bed and later learns she is terminally ill, and is told that she will die with certainty. The doctor admits to a 2% margin of error, but insists that Sarah's death is certain. To save those she cares about from the pain of losing her, Sarah opts for a cloning procedure of herself to take her place.

Sarah dubs her clone "Sarah's Double" and gives her the basic knowledge of her interests and lifestyle. Ten months later, Sarah is informed that she has, inexplicably, gone into full remission, and that she is going to live. When she arrives at her mother's house to share the good news, she finds Peter and Sarah's Double there and is furious to discover that Sarah's Double had been in contact with her mother for quite some time, against her wishes. The truth now exposed, Sarah tries to return things to normal and demands her clone to be "decommissioned", only to be rejected by Peter, as well as her mother, both of whom prefer the clone.

Sarah is told that Sarah's Double has requested to stay alive, meaning that, by law, they will have to participate in a publicized duel to the death in a year that they must prepare for. Having to pay for her clone as well as herself, Sarah soon takes up self-defense and combat classes with a trainer, Trent. For the next year, Sarah improves herself both physically and mentally, learning to tolerate violence, and how clone duels operate. In lieu of payment for the final month of training, she teaches Trent hip-hop dancing. Feeling confident, Sarah meets up with Peter to state that she means no ill will but promises to unapologetically kill her clone.

While in the middle of a test with Trent, Sarah spots her clone watching from outside and chases her to a nearby playground. There, they talk over their situation before Sarah's Double takes Sarah to a support group for people who survived their duels. Outside, the two bond and agree to escape past the border to live their lives. The next morning, the two hike through a forest where Sarah discovers that Sarah's Double has poisoned her water.

Sarah's Double eventually shows up late to the duel alone, lying that she is the original and stating that the "clone" has fled. After an investigation and a court hearing, a judge declares her to be the original, freeing her to take over as the only Sarah. However, Sarah's Double is soon left feeling just as depressed and unfulfilled as the original Sarah, carrying her burdens such as the unfiltered Peter and her doting mother (who both know she is the clone). While out driving, Sarah's Double stops in the middle of a roundabout and cries. (thanks to Wikipedia)