"Wrong Side of the Rainbow" explores the painful journey through love's darkest corners. When her first love, Win, abruptly leaves her, Pie's faith in love shatters. She eventually finds healing and completeness with Pun, marrying him in hopes of a true fresh start. Yet, her newfound happiness is drastically tested when Win returns, not as a ghost of the past, but as Pun's inseparable close friend. Old feelings violently resurface as Win's love for Pie reignites, forcing Pie to confront the uncomfortable truth: she has never truly moved on. As deep-buried family secrets emerge, Pun's life is plunged into turmoil. Caught in a complex web of love, lies, and resentment, Pie, Pun, and Win must face their deepest emotions and confront their intertwined past before everything they cherish is irrevocably torn apart. This gripping Thai film uncovers the true cost of unresolved feelings.