The Hunger Games return with such a sequel twist that you can't believe writer Suzanne Collins didn't think of film when writing. Catching Fire builds up with all types of subversive messaging which is interesting but also brings into relief the limitations of the genre and film.
A college student in Paris hired by professional extractor Dom Cobb to become his team's new Architect. Her exceptional intellect and creativity make her an ideal candidate for the position.
Ariadne was first approached by Cobb at her university in Paris after she was recommended for the job as Architect by her professor (Cobb's mentor and father-in-law), which is the job of designing the layout of each dream and creating traps and mazes. Their previous Architect, Nash, was found out by Saito and taken to Cobel Engineering (the company that hired the original team along with Cobb and Arthur) and since the projection of Cobb's deceased wife, Mal, finds a way to sabotage his subconscience he can no longer be an architect because what he knows she knows as well. Ariadne is in trained to learn about the rules and properties of the dream world and picks up the basics very quickly. However as she goes too far with them (messing with the physics and creating from memory) Cobb's projections turn on her, the projection of Mal stabs her, she wakes up and leaves out of fear of the terror of Cobb's sub-conscience.
As Cobb predicted, Ariadne not so reluctantly returns, because there's just nothing quite like it; "It's just... pure creation". Arthur is the one that trains her this time on how to create traps using mazes and Escher-like paradoxes such as the Penrose Staircase -- a never ending staircase or rather one that loops over and over again. Arthur eventually tells Ariadne that Mal is dead and Cobb later informs her that he had been charged with murdering her, which it still isn't clear whether that is true or not. Ariadne is still somewhat distressed about Cobb's sub-conscience and when she sees him wired in to the dream device alone one night she enters into his dream without permission. After seeing some of the horrifying memories of Mal that Cobb has trapped within his sub-conscience, Ariadne insists she accompanies Cobb in the Inception job since at least someone in the team needs to know what's going in Cobb's mind.