In a world of mistaken identities and dark retribution, "Retta Thala" takes a gripping dive into the consequences of a serendipitous encounter between two men: Kaali, an orphaned Pondicherry youth, and Malpe Upendra, his doppelganger from Goa with a shady past. As their lives become irreversibly intertwined, corrupt cop Thiraviyam and Upendra's enemies join forces to put an end to the identity swaps that have brought chaos into their lives. The action unfolds in this tense thriller, where loyalty is tested and identities are forever altered.