Emma is the daughter of Olivia Kirschner and an unknown father. She was born for the purpose of infiltrating Project Splinter, and to complete Titan's ability to generate a massive time-ending paradox and the Army of the 12 Monkey's Red Forest.
Olivia gave birth to Emma when she was a teenager. During her pregnancy, she was told by the Witness (who is in fact Olivia at the end of time) that she must sacrifice her daughter. Mantis, Olivia's mother and Emma's grandmother protests this, having started to lose faith in the Witness and the Army, but the zealous Olivia proceeds anyway. She leaves the baby Emma at the base of a tree where she is picked up by the Witness.
Emma is raised in a highly academic environment in order to fulfill the Witness's purpose for her, which is to infiltrate Project Splinter—the time-travel research group lead by Elliot Jones and his wife Katarina Jones—in order to gain the necessary knowledge to complete Titan and its function of creating the Army's prophesized Red Forest.
She successfully joins Project Splinter and is shown to be close to Eliot and to have the respect of Katarina, who saw her as extremely bright.
While running an experiment on Project Splinter, a miscalculation in Emma's program causes Eliot to stop the experiment and reveal that it could have led to a Hartle-Hawking State (the Army's Red Forest).
Emma is taken to Titan by the Army in order to complete Titan's systems and the Hartle-Hawking calculations. Olivia shows her no maternal compassion, emphasizing that Emma was born for this mission, and "to learn, not to feel." When Emma accidentally calls her "mother," Olivia threatens to kill her by hanging her over the edge of her tower.
Her treatment by her mother and the Army, and seeing Jones' love for her daughter Hannah while she is tortured on Titan, leads Emma to contemplate suicide. She decides not to and to instead take her fate into her own hands. She escapes back to the past through one of Titan's Machines—though not before already having entered the Red Forest calculations—where she takes up the name "Marion Woods." She later comments that this was the first decision she ever made for her life.
When Hannah is sent back in time by Jones to find out what a full life is, she is also given a final mission to complete, which is to find "Marion Woods," Cole's mother and the origin of the Serpent and Demon tale. Jones had found out that Marion would be at a certain bar on March 8, 2009. Hannah shows up there and finds Emma, leading to a fight between them when Emma mistakes her for an agent of the 12 Monkeys. They escape together when a 12 Monkeys member starts shooting at them, and Emma fills Hannah in on the Witness's plans.
While on the run, and driving on a country road, Emma and Hannah are driven off the road by another 12 Monkeys member. They hit a tree and Emma is shot. They flee into the woods and eventually stumble on Matthew Cole's trailer, who drives Emma to the nearby hospital. However, it's too late and Emma dies.
It is revealed later that Hannah takes on Emma's pseudonym of "Marion Woods," and is in fact James Cole's mother, and not Emma.