In 'I'll Be You,' identical twins Sam and Elli—once inseparable and co-stars as child actors—have found their lives veering down tragically different paths. Sam's struggle with addiction has left her grappling with the remnants of a failed Hollywood career, while Elli, the seemingly perfect homemaker, faces turmoil of her own after adopting a two-year-old girl and her sudden retreat to a mysterious spa. When Elli vanishes, the estranged sisters are drawn back into each other's orbits, and Sam must confront the complexities of their shared bond to unravel the enigmatic disappearance. As the search reveals dark family secrets and twisted realities, the sisters learn that their childhood phrase, 'You be me, and I'll be you,' bears more truth and danger than they ever could have imagined.