Rhoda Williams, portrayed by Brit Marling, is a high school student and aspiring astronomer who has just received acceptance into MIT. In celebration with friends, she drives home under the influence and becomes captivated by a remarkable story on the radio about a newly visible planet in the sky. In an unfortunate turn of fate, she crashes into a stationary vehicle at an intersection, leading to the tragic death of John Burroughs's (William Mapother) pregnant wife and son, while John himself falls into a coma. As a consequence of her actions, Rhoda is sentenced to four years in prison, but her juvenile status keeps her identity shielded from the public eye.
Upon her release, Rhoda returns to her parents' home, where she learns that the mysterious new planet, later named ‘Earth 2’, has come alarmingly close to our own. This alternate world mirrors Earth, complete with identical cities and landscapes, sparking interest from scientists trying to make contact despite interference from Earth’s own broadcasts. Rhoda's brother informs her about an essay contest held by millionaire Keith Harding, who is funding a space voyage to this new planet, offering a free ticket to the most compelling candidate. Recognizing her diminished prospects of re-entering the academic world, Rhoda opts for a job as a janitor in a local school, finding solace in physical labor while minimizing social interactions.
As she navigates her guilt and memories of the past, Rhoda returns to the scene of the accident, where she confronts John. He is seen leaving a toy in memory of his lost family, prompting her to shadow him to his home. Paralyzed by guilt and uncertainty, she observes him from a distance, leading to a near-freezing encounter before being rescued. During her recovery, Rhoda decides to enter the essay competition, arguing that as an ex-convict, she embodies the spirit of exploration that has historically been represented by outcasts.
Through an online search, Rhoda discovers John's past as an acclaimed composer who awoke from his coma only to learn of his family’s demise post-burial. Battling with her overwhelming guilt, she visits John's residence, but instead, she poses as a maid, presenting a free cleaning service to him. Oblivious to Rhoda’s true identity, John welcomes her help, and their relationship begins to blossom within the confines of grief and healing. They share conversations on astronomy and play a video game, fostering a bond tinged with both mutual respect and shared loss.
As the scientists finally make successful contact with Earth 2, revealing the existence of exact duplicates of individuals from Earth, the excitement and intrigue intensify. Rhoda continues to clean John's home, deepening their connection, yet her conscience looms over her like a persistent shadow. On one particularly poignant evening, during a discussion about the dual existences on Earth 2, she expresses a desire to prepare for her copy, saying, > "Better luck next time," before revealing her name, Rhoda, further clouding John's understanding of her true identity.
Conflict arises when John discovers remnants of his late wife’s belongings, igniting his anger and hurt. Though their feelings for each other deepen, the ghosts of their pasts stand in the way. Rhoda's internal struggle intensifies as she grapples with her conscience, leading her to a visit to the hospital to see Purdeep, a blind and deaf janitor whose own struggles resonate with her.
The culmination of her emotional journey leads her to eventually win the coveted spot on the flight to Earth 2, a momentous occasion that is bittersweet. Torn between her ambition and her connection with John, the inevitable conflict arises when she shares her plans with him. The weight of her past actions presses down on her, forcing her to recount her regret of destroying his family.
Distraught over her confession, John initially pushes her away. When she returns home and confronts the media frenzy that her past has unleashed, she's entangled in the chaos of her newfound notoriety. However, she finds the strength to confront John one last time, sharing with him a theory that suggests the possibility of their loved ones still existing on Earth 2.
Months later, as she grapples with her past and future, Rhoda watches a broadcast about the upcoming space flight with John preparing for the journey. Just as she thinks she’s coming to terms with her life, she faces a startling revelation — her doppelgänger from Earth 2 stands before her, clad in vibrant clothing that starkly contrasts Rhoda's own life, igniting a whirlwind of emotions as the line between identities blurs.
